There is no evidence that any treatment for hangovers is very effective.

- Rehydration: Drinking water before going to bed or during hangover may relieve dehydration-associated symptoms such as thirst, dizziness, dry mouth, and headache.

- Non-steroidal anti-inflammatory drugs such as aspirin or ibuprofen have been proposed as a treatment for the headaches associated with a hangover. There however is no evidence to support a benefit, and there are concerns that taking alcohol and aspirin together may increase the risk of stomach bleeding and liver damage.

- Tolfenamic acid, an inhibitor of prostaglandin synthesis, in a 1983 study reduced headache, nausea, vomiting, irritation but had no effect on tiredness in 30 people.

- Pyritinol: A 1973 study found that large doses (several hundred times the recommended daily intake) of Pyritinol, a synthetic Vitamin B6 analog, can help to reduce hangover symptoms. Possible side effects of pyritinol include hepatitis (liver damage) due to cholestasis and acute pancreatitis.

- Yeast-based extracts: The difference in the change for discomfort, restlessness, and impatience were statistically significant but no significant differences on blood chemistry parameters, blood alcohol or acetaldehyde concentrations have been found, and it did not significantly improve general well-being.

Recommendations for foods, drinks and activities to relieve hangover symptoms abound. The ancient Romans, on the authority of Pliny the Elder, favored raw owl's eggs or fried canary, while the "prairie oyster" restorative, introduced at the 1878 Paris World Exposition, calls for raw egg yolk mixed with Worcestershire sauce, Tabasco sauce, salt and pepper. By 1938, the Ritz-Carlton Hotel provided a hangover remedy in the form of a mixture of Coca-Cola and milk (Coca-Cola itself having been invented, by some accounts, as a hangover remedy). Alcoholic writer Ernest Hemingway relied on tomato juice and beer. Other purported hangover cures include cocktails such as Bloody Mary or Black Velvet (consisting of equal parts champagne and stout). A 1957 survey by an American folklorist found widespread belief in the efficacy of heavy fried foods, tomato juice and sexual activity.

Other untested or discredited treatments include:

- Hair of the dog: The belief is that consumption of further alcohol after the onset of a hangover will relieve symptoms, based upon the theory that the hangover represents a form of alcohol withdrawal and that by satiating the body's need for alcohol the symptoms will be relieved. Social drinkers and alcoholics claim that drinking more alcohol gives relief from hangover symptoms, but research shows that the use of alcohol as a hangover cure seems to predict current or future problem drinking and alcohol use disorder, through negative reinforcement and the development of physical dependence. While the practice is popular in tradition and promoted by many sellers of alcoholic beverages, medical opinion holds that the practice merely postpones the symptoms, and courts addiction. Favored choices include Fernet Branca and Bloody Mary.

- Kudzu ("Pueraria montana var. lobata"): The main ingredient in remedies such as kakkonto. A study concluded, "The chronic usage of "Pueraria lobata" at times of high ethanol consumption, such as in hangover remedies, may predispose subjects to an increased risk of acetaldehyde-related neoplasm and pathology. ... Pueraria lobata appears to be an inappropriate herb for use in herbal hangover remedies as it is an inhibitor of ALDH2."

- Artichoke: Research shows that artichoke extract does not prevent the signs and symptoms of alcohol-induced hangover.

- Sauna or steam-bath: Medical opinion holds this may be dangerous, as the combination of alcohol and hyperthermia increases the likelihood of dangerous cardiac arrhythmias.

- Oxygen: There have been anecdotal reports from those with easy access to a breathing oxygen supply – medical staff, and military pilots — that oxygen can also reduce the symptoms of hangovers sometimes caused by alcohol consumption. The theory is that the increased oxygen flow resulting from oxygen therapy improves the metabolic rate, and thus increases the speed at which toxins are broken down. However, one source states that (in an aviation context) oxygen has no effect on physical impairment caused by hangover.

- Fructose and glucose: Glucose and fructose significantly inhibit the metabolic changes produced by alcohol intoxication, nevertheless they have no significant effect on hangover severity.

- Vitamin B: No effects on alcohol metabolism, peak blood alcohol and glucose concentrations have been found and psychomotor function is not significantly improved when using Vitamin B supplements.

- Caffeinated drinks: No significant correlation between caffeine use and hangover severity has been found.

Many drugs taken to relieve typical symptoms of motion sickness (including nausea, dizziness, etc.) contain compounds that may exacerbate drowsiness. Antihistamines are commonly used to treat motion sickness; however, side effects include drowsiness and impaired cognitive abilities. Anticholinergics such as scopolamine have also proved effective against motion sickness, but may induce drowsiness. These treatments may be combined with stimulants to counteract typical motion-induced nausea and dizziness while also preventing sedation.

However, many stimulants possess addictive properties, which result in a high potential for substance abuse. Some stimulants also tend to interfere with normal sleep patterns. Modafinil has been studied as a possible treatment for the sopite syndrome that does not appear to have the same side effects of normal stimulants. Modafanil appears to be effective when taken in combination with anticholinergics such as scopolamine, but studies of Modafanil-only treatments for motion sickness remain inconclusive.

Ondansetron, a 5HT3 antagonist, appears to have promise as a treatment.

Alcoholics may also require treatment for other psychotropic drug addictions and drug dependences. The most common dual dependence syndrome with alcohol dependence is benzodiazepine dependence, with studies showing 10–20 percent of alcohol-dependent individuals had problems of dependence and/or misuse problems of benzodiazepine drugs such as valium or clonazopam. These drugs are, like alcohol, depressants. Benzodiazepines may be used legally, if they are prescribed by doctors for anxiety problems or other mood disorders, or they may be purchased as illegal drugs "on the street" through illicit channels. Benzodiazepine use increases cravings for alcohol and the volume of alcohol consumed by problem drinkers. Benzodiazepine dependency requires careful reduction in dosage to avoid benzodiazepine withdrawal syndrome and other health consequences. Dependence on other sedative-hypnotics such as zolpidem and zopiclone as well as opiates and illegal drugs is common in alcoholics. Alcohol itself is a sedative-hypnotic and is cross-tolerant with other sedative-hypnotics such as barbiturates, benzodiazepines and nonbenzodiazepines. Dependence upon and withdrawal from sedative-hypnotics can be medically severe and, as with alcohol withdrawal, there is a risk of psychosis or seizures if not managed properly.

To relieve reactive hypoglycemia, the NIH recommends taking the following steps:

- Avoiding or limiting sugar intake;

- Exercising regularly; exercise increases sugar uptake which decreases excessive insulin release

- Eating a variety of foods, including meat, poultry, fish, or nonmeat sources of protein, foods such as whole-grains, fruits, nuts, vegetables, and dairy products;

- Choosing high-fiber foods.

Other tips to prevent sugar crashes include:

- Avoiding eating meals or snacks composed entirely of carbohydrates; simultaneously ingest fats and proteins, which have slower rates of absorption.

- Consistently choosing longer lasting, complex carbohydrates to prevent rapid blood-sugar dips in the event that one does consume a disproportionately large amount of carbohydrates with a meal

- Monitoring any effects medication may have on symptoms.

Low-carbohydrate diet and/or frequent small split meals is the first treatment of this condition. The first important point is to add small meals at the middle of the morning and of the afternoon, when glycemia would start to decrease. If adequate composition of the meal is found, the fall in blood glucose is thus prevented. Patients should avoid rapidly absorbable sugars and thus avoid popular soft drinks rich in glucose or sucrose. They should also be cautious with drinks associating sugar and alcohol, mainly in the fasting state.

As it is a short-term ailment, a sugar crash does not usually require medical intervention in most people. The most important factors to consider when addressing this issue are the composition and timing of foods.

Acute low blood sugar symptoms are best treated by consuming small amounts of sweet foods, so as to regain balance in the body’s carbohydrate metabolism. Suggestions include sugary foods that are quickly digested, such as:

- Dried fruit

- Soft drinks

- Juice

- Sugar as sweets, tablets or cubes.

These headaches are treated by determining the cause of the headache and treating or removing this cause

Sobriety is the condition of not having any measurable levels, or effects from mood-altering drugs. According to WHO "Lexicon of alcohol and drug terms..." sobriety is continued abstinence from psychoactive drug use. Sobriety is also considered to be the natural state of a human being given at a birth. In a treatment setting, sobriety is the achieved goal of independence from consuming or craving mind-altering substances. As such, sustained abstinence is a prerequisite for sobriety. Early in abstinence, residual effects of mind-altering substances can preclude sobriety. These effects are labeled "PAWS", or "post acute withdrawal syndrome". Someone who abstains, but has a latent desire to resume use, is not considered truly sober. An abstainer may be subconsciously motivated to resume drug use, but for a variety of reasons, abstains (e.g. such as a medical or legal concern precluding use). Sobriety has more specific meanings within specific contexts, such as the culture of Alcoholics Anonymous, other 12 step programs, law enforcement, and some schools of psychology. In some cases, sobriety implies achieving "life balance".

The most straightforward way to avoid nitrogen narcosis is for a diver to limit the depth of dives. Since narcosis becomes more severe as depth increases, a diver keeping to shallower depths can avoid serious narcosis. Most recreational dive schools will only certify basic divers to depths of , and at these depths narcosis does not present a significant risk. Further training is normally required for certification up to on air, and this training should include a discussion of narcosis, its effects, and cure. Some diver training agencies offer specialized training to prepare recreational divers to go to depths of , often consisting of further theory and some practice in deep dives under close supervision. Scuba organizations that train for diving beyond recreational depths, may forbid diving with gases that cause too much narcosis at depth in the average diver, and strongly encourage the use of other breathing gas mixes containing helium in place of some or all of the nitrogen in air – such as trimix and heliox – because helium has no narcotic effect. The use of these gases forms part of technical diving and requires further training and certification.

While the individual diver cannot predict exactly at what depth the onset of narcosis will occur on a given day, the first symptoms of narcosis for any given diver are often more predictable and personal. For example, one diver may have trouble with eye focus (close accommodation for middle-aged divers), another may experience feelings of euphoria, and another feelings of claustrophobia. Some divers report that they have hearing changes, and that the sound their exhaled bubbles make becomes different. Specialist training may help divers to identify these personal onset signs, which may then be used as a signal to ascend to avoid the narcosis, although severe narcosis may interfere with the judgement necessary to take preventive action.

Deep dives should be made only after a gradual training to test the individual diver's sensitivity to increasing depths, with careful supervision and logging of reactions. Diving organizations such as Global Underwater Explorers (GUE) emphasize that such sessions are for the purpose of gaining experience in recognizing the onset symptoms of narcosis for an individual , which are somewhat more repeatable than for the average group of divers. Scientific evidence does not show that a diver can train to overcome any measure of narcosis at a given depth or become tolerant of it.

Equivalent narcotic depth (END) is a commonly used way of expressing the narcotic effect of different breathing gases. The National Oceanic and Atmospheric Administration (NOAA) Diving Manual now states that oxygen and nitrogen should be considered equally narcotic. Standard tables, based on relative lipid solubilities, list conversion factors for narcotic effect of other gases. For example, hydrogen at a given pressure has a narcotic effect equivalent to nitrogen at 0.55 times that pressure, so in principle it should be usable at more than twice the depth. Argon, however, has 2.33 times the narcotic effect of nitrogen, and is a poor choice as a breathing gas for diving (it is used as a drysuit inflation gas, owing to its low thermal conductivity). Some gases have other dangerous effects when breathed at pressure; for example, high-pressure oxygen can lead to oxygen toxicity. Although helium is the least intoxicating of the breathing gases, at greater depths it can cause high pressure nervous syndrome, a still mysterious but apparently unrelated phenomenon. Inert gas narcosis is only one factor influencing the choice of gas mixture; the risks of decompression sickness and oxygen toxicity, cost, and other factors are also important.

Because of similar and additive effects, divers should avoid sedating medications and drugs, such as marijuana and alcohol before any dive. A hangover, combined with the reduced physical capacity that goes with it, makes nitrogen narcosis more likely. Experts recommend total abstinence from alcohol for at least 12 hours before diving, and longer for other drugs. Abstinence time needed for marijuana is unknown, but owing to the much longer half-life of the active agent of this drug in the body, it is likely to be longer than for alcohol.

The only reliable treatment, and in many cases the only option available, is to descend. Attempts to treat or stabilize the patient "in situ" (at altitude) are dangerous unless highly controlled and with good medical facilities. However, the following treatments have been used when the patient's location and circumstances permit:

- Oxygen may be used for mild to moderate AMS below and is commonly provided by physicians at mountain resorts. Symptoms abate in 12 to 36 hours without the need to descend.

- For more serious cases of AMS, or where rapid descent is impractical, a Gamow bag, a portable plastic hyperbaric chamber inflated with a foot pump, can be used to reduce the effective altitude by as much as . A Gamow bag is generally used only as an aid to evacuate severe AMS patients, not to treat them at altitude.

- Acetazolamide 250 mg twice daily dosing assists in AMS treatment by quickening altitude acclimatization. A study by the Denali Medical Research Project concluded: "In established cases of acute mountain sickness, treatment with acetazolamide relieves symptoms, improves arterial oxygenation, and prevents further impairment of pulmonary gas exchange."

- The folk remedy for altitude sickness in Ecuador, Peru and Bolivia is a tea made from the coca plant. See mate de coca.

- Steroids can be used to treat the symptoms of pulmonary or cerebral edema, but do not treat the underlying AMS.

- Two studies in 2012 showed that Ibuprofen 600 milligrams three times daily was effective at decreasing the severity and incidence of AMS; it was not clear if HAPE or HACE was affected.

Increased water intake may also help in acclimatization to replace the fluids lost through heavier breathing in the thin, dry air found at altitude, although consuming excessive quantities ("over-hydration") has no benefits and may cause dangerous hyponatremia.

The sopite syndrome may be difficult to test due to the nature of the symptoms. Indicators such as drowsiness, mood changes, and apathy must be observed and graded objectively. Therefore, many of the results obtained from studies of the sopite syndrome are not sufficiently repeatable for the purposes of scientific writing.

Injury is defined as damage or harm that is done or sustained. The potential of injuring oneself or others can be increased after consuming alcohol due to the certain short term effects related to the substance such as lack of coordination, blurred vision, and slower reflexes to name a few. Due to these effects the most common injuries include head, fall, and vehicle related injuries. These include a range of soft tissue damage and fractures. A study was conducted between November 1, 2001 and June 30, 2002 of patients admitted to The Ulster Hospital in Northern Ireland with fall related injuries. They found that 113 of those patients admitted to that hospital during that had consumed alcohol recently and that the injury severity was higher for those that had consumed alcohol compared to those that hadn't. Another study showed that 21% of patients admitted to the Emergency Department of the Bristol Royal Infirmary had either direct or indirect alcohol related injuries. If these figures are extrapolated it shows that the estimated number of patients with alcohol related injuries are over 7000 during the year at this ED alone.

In the United States alcohol resulted in about 88,000 deaths in 2010.

Narcosis is potentially one of the most dangerous conditions to affect the scuba diver below about . Except for occasional amnesia of events at depth, the effects of narcosis are entirely removed on ascent and therefore pose no problem in themselves, even for repeated, chronic or acute exposure. Nevertheless, the severity of narcosis is unpredictable and it can be fatal while diving, as the result of illogical behavior in a dangerous environment.

Tests have shown that all divers are affected by nitrogen narcosis, though some experience lesser effects than others. Even though it is possible that some divers can manage better than others because of learning to cope with the subjective impairment, the underlying behavioral effects remain. These effects are particularly dangerous because a diver may feel they are not experiencing narcosis, yet still be affected by it.

If there is no hypoglycemia at the time of the symptoms, this condition is called "postprandial syndrome." It might be an "adrenergic postprandial syndrome" — blood glucose levels are normal, but the symptoms are caused through autonomic adrenergic counterregulation. Often, this syndrome is associated with emotional distress and anxious behaviour of the patient. This is often seen in dysautonomic disorders as well. Dietary recommendations for reactive hypoglycemia can help to relieve symptoms of postprandial syndrome.

Headaches due to environmental causes are usually diagnosed by taking an exposure history.

Alcohol intolerance is due to a genetic deficiency of the enzyme alcohol dehydrogenase, the enzyme that metabolises ingested alcohol. It can also be an effect or side effect associated with certain drugs such as disulfiram, metronidazole, or nilutamide. It is characterized as intolerance of and unpleasant symptoms upon the ingestion of alcohol, causing hangover symptoms similar to the "disulfiram-like reaction" of aldehyde dehydrogenase deficiency or chronic fatigue syndrome.

If people are intolerant, some nearly non-alcoholic beverages may be a problem, similar to alcohol-containing medications, vinegar, inhalation of alcohol or the vapour of alcohol-containing cleaning agents.

Drinking alcohol first or afterwards together with Calcium cyanamide, an inorganic compound used as a fertilizer, can cause permanent or long lasting intolerance (nitrolime disease), contributing together with other substances to the accumulation of harmful Acetaldehyde by inhibiting the enzyme acetaldehyde dehydrogenase.

A drug-related blackout is a phenomenon caused by the intake of any substance or medication in which short term and long term memory creation is impaired, therefore causing a complete inability to recall the past. Blackouts are most frequently associated with GABAergic drugs. Blackouts are frequently described as having effects similar to that of anterograde amnesia, in which the subject cannot recall any events after the event that caused amnesia. Research on alcohol blackouts was begun by E. M. Jellinek in the 1940s. Using data from a survey of Alcoholics Anonymous (AA) members, he came to believe that blackouts would be a good determinant of alcoholism. However, there are conflicting views whether this is true. The negative psychological effects of an alcohol-related blackout are often worsened by those who suffer from anxiety disorders. Impairment of the liver will also allow more alcohol to reach the brain and hasten the individual's blackout.

The term "blackout" can also refer to a complete loss of consciousness, or syncope.

Alcohol dependence is not prerequisite to blackouts (either en bloc or fragmentary). Students in one study who reported blackouts were demographically similar to other drinking students. Importantly, however, students reporting blackouts drank more, and had other symptoms of alcoholic drinking, even though they did not fall into the alcoholic range on the Michigan Alcoholism Screening Test (MAST). Half of the students reported having had a blackout during their drinking careers, which closely followed other research findings.

In another study 25% of healthy college students reported being familiar with alcoholic blackouts. 51% of the students reported that they had had at least one blackout. Blackouts were reported during activities such as spending money (27%), sexual conduct (24%), fighting (16%), vandalism (16%), unprotected intercourse (6%), and driving a car (3%). So a significant number of students were engaged in a range of possibly hazardous activities during blackouts.

Of 545 individuals in another study, 161 (29.5%) reported driving drunk, 139 (25.5%) reported a regretted sexual situation, 67 (12.3%) reported unprotected sex, 60 (11%) reported having damaged property, 55 (10.1%) reported getting into a physical fight, and 29 (5.3%) reported injuring someone while under the influence of alcohol in the past 6 months.

Horizontal Gaze Nystagmus (HGN) testing is a common practice used by law enforcement in the United States in the identification of persons who are intoxicated or under the influence of a controlled substance. The key difference between recognizing PAN and horizontal gaze nystagmus is the position of the subject's head in relation to the body. PAN is identified when the head is tilted to one side or the other. In order for HGN to be properly identified, the head must be positioned in line with the spine. Because of this, if the head is tilted towards the side when an evaluation for HGN is given, PAN may be induced and give a "false positive" for HGN. Some defendants may claim or argue that the nystagmus observed by an officer was positional and not horizontal gaze.

The overstimulation of the semicircular canals during PAN I and PAN II is associated with the unsteadiness, nausea, and vertigo felt by intoxicated people. PAN I is more associated with postural problems (e.g. standing and walking) while PAN II has been more associated with the feelings of a hangover.

There is a brief period between PAN I and PAN II when the alcohol concentrations in the canal membrane and extracellular fluid are in equilibrium. During this time, neither PAN I nor PAN II is present.

Ethanol is the type of alcohol found in alcoholic beverages. It is a volatile, flammable, colorless liquid that acts as a central nervous system depressant. Ethanol can impair different types of memory.

"Prospective memory" involves remembering to carry out an intended action in the future without an explicit reminder. Alcohol has been found to impair this ability. Chronic heavy alcohol users report significantly more prospective forgetting compared to low-dose and alcohol-free controls. The Prospective Memory Questionnaire assesses short-term habitual prospective memory, long-term episodic prospective memory, and internally cued prospective memory. Chronic heavy alcohol users reported significantly greater deficits for all three aspects of prospective memory. Individuals that report heavy alcohol use report 24% more difficulties with prospective memory than those who report that they are light drinkers and 30% more difficulties than those who report that they never drink. The effects of alcohol on prospective memory can also be assessed in the laboratory by simulating prospective memory tasks that individuals face in everyday life. Individuals who are given 0.6 g/kg alcohol prior to performing prospective memory tasks do significantly poorer than a placebo group. Alcohol can damage the prefrontal and frontal areas of the brain, and this may be responsible for prospective memory impairments since prospective memory performance is highly correlated with frontal executive functions.