Research has found that drinking reduces the risk of developing gallstones. Compared with alcohol abstainers, the relative risk of gallstone disease, controlling for age, sex, education, smoking, and body mass index, is 0.83 for occasional and regular moderate drinkers (< 25 ml of ethanol per day), 0.67 for intermediate drinkers (25-50 ml per day), and 0.58 for heavy drinkers. This inverse association was consistent across strata of age, sex, and body mass index." Frequency of drinking also appears to be a factor. "An increase in frequency of alcohol consumption also was related to decreased risk. Combining the reports of quantity and frequency of alcohol intake, a consumption pattern that reflected frequent intake (5-7 days/week) of any given amount of alcohol was associated with a decreased risk, as compared with nondrinkers. In contrast, infrequent alcohol intake (1-2 days/week) showed no significant association with risk."

A large self-reported study published in 1998 found no correlation between gallbladder disease and multiple factors including smoking, alcohol consumption, hypertension, and coffee consumption. A retrospective study from 1997 found vitamin C (ascorbic acid) supplement use in drinkers was associated with a lower prevalence of gallbladder disease, but this association was not seen in non-drinkers.

Having a particular genetic variant (A-allele of ADH1B rs1229984) is associated with non-drinking and lower alcohol consumption. This variant is also associated with favorable cardiovascular profile and a reduced risk of coronary heart disease compared to those without the genetic variant, but it is unknown whether this may be caused by differences in alcohol consumption or by additional confounding effects of the genetic variant itself.

The impact of alcohol on weight-gain is contentious: some studies find no effect, others find decreased or increased effect on weight gain.

Alcohol use increases the risk of chronic gastritis (stomach inflammation); it is one cause of cirrhosis, hepatitis, and pancreatitis in both its chronic and acute forms.

An alcohol enema is a faster method of alcohol intoxication since the alcohol is absorbed directly into the bloodstream. The lower gastrointestinal tract lacks the alcohol dehydrogenase enzyme present in the stomach and liver that breaks down ethanol into acetylaldehyde, which is actually more toxic than ethanol (drinking alcohol) and is responsible for most chronic effects of ethanol. When rectally absorbed, ethanol will still eventually arrive at the liver, but the high alcohol content could overwhelm the organ. Additionally, consuming the alcohol rectally neutralizes the body's ability to reject the toxin by vomiting.

While little detailed genetic research has been done, it has been shown that alcoholism tends to run in families with possible involvement of differences in alcohol metabolism and the genotype of alcohol-metabolizing enzymes.

Two reported alcohol enema techniques are via an alcohol-soaked tampon or a funnel, such as a beer bong, inserted into the rectum.

Alcohol abuse is said to be most common in people aged between 15 and 24 years, according to Moreira 2009. However, this particular study of 7275 college students in England collected no comparative data from other age groups or countries.

Causes of alcohol abuse are complex and are likely the combination of many factors, from coping with stress to childhood development. The US Department of Health & Human Services identifies several factors influencing adolescent alcohol use, such as risk-taking, expectancies, sensitivity and tolerance, personality and psychiatric comorbidity, hereditary factors, and environmental aspects. Studies show that child maltreatment such as neglect, physical, and/or sexual abuse, as well as having parents with alcohol abuse problems, increases the likelihood of that child developing alcohol use disorders later in life. According to Shin, Edwards, Heeren, & Amodeo (2009), underage drinking is more prevalent among teens that experienced multiple types of childhood maltreatment regardless of parental alcohol abuse, putting them at a greater risk for alcohol use disorders. Genetic and environmental factors play a role in the development of alcohol use disorders, depending on age. The influence of genetic risk factors in developing alcohol use disorders increase with age ranging from 28% in adolescence and 58% in adults.

The tolerance to alcohol is not equally distributed throughout the world's population, and genetics of alcohol dehydrogenase indicate resistance has arisen independently in different cultures. In North America, Native Americans have the highest probability of developing alcoholism compared to Europeans and Asians.

Higher body masses and the prevalence of high levels of alcohol dehydrogenase in an individual increase alcohol tolerance.

Not all differences in tolerance can be traced to biochemistry. Differences in tolerance levels are also influenced by socio-economic and cultural difference including diet, average body weight and patterns of consumption.

An estimated one out of twenty people have an alcohol flush reaction. It is not in any way an indicator for the drunkenness of an individual. It is colloquially known as "face flush", a condition where the body metabolizes alcohol nearly 100-times less efficiently into acetaldehyde, a toxic metabolite. Flushing, or blushing, is associated with the erythema (reddening caused by dilation of capillaries) of the face, neck, and shoulder, after consumption of alcohol.

Direct alcohol tolerance is largely dependent on body size. Large-bodied people will require more alcohol to reach insobriety than lightly built people. Thus men, being larger than women on average, will have a higher alcohol tolerance. The alcohol tolerance is also connected with activity of "alcohol dehydrogenases" (a group of enzymes responsible for the breakdown of alcohol) in the liver, and in the bloodstream.

High level of alcohol dehydrogenase activity results in fast transformation of ethanol to more toxic acetaldehyde. Such atypical alcohol dehydrogenase levels are less frequent in alcoholics than in nonalcoholics and, alongside other symptoms, can indicate various forms of liver disease. Furthermore, among alcoholics, the carriers of this atypical enzyme consume lower ethanol doses, compared to the individuals without the allele.

About 12% of American adults have had an alcohol dependence problem at some time in their life. In the UK the NHS estimates that around 9% of men and 4% of UK women show signs of alcohol dependence.

Based on combined data from SAMHSA's 2004–2005 National Surveys on Drug Use & Health, the rate of past-year alcohol dependence or abuse among persons aged 12 or older varied by level of alcohol use: 44.7% of past month heavy drinkers, 18.5% binge drinkers, 3.8% past month non-binge drinkers, and 1.3% of those who did not drink alcohol in the past month met the criteria for alcohol dependence or abuse in the past year. Males had higher rates than females for all measures of drinking in the past month: any alcohol use (57.5% vs. 45%), binge drinking (30.8% vs. 15.1%), and heavy alcohol use (10.5% vs. 3.3%), and males were twice as likely as females to have met the criteria for alcohol dependence or abuse in the past year (10.5% vs. 5.1%).

The cause of alcohol abuse is complex. Alcohol abuse is related to economic and biological origins and is associated with adverse health consequences. Peer pressure influences individuals to abuse alcohol; however, most of the influence of peers is due to inaccurate perceptions of the risks of alcohol abuse. According to Gelder, Mayou and Geddes (2005) easy accessibility of alcohol is one of the reasons people engage in alcohol abuse as this substance is easily obtained in shops. Another influencing factor among adolescents and college students are the perceptions of social norms for drinking; people will often drink more to keep up with their peers, as they believe their peers drink more than they actually do. They might also expect to drink more given the context (e.g. sporting event, fraternity party, etc.). This perception of norms results in higher alcohol consumption than is normal.

Alcohol abuse is also associated with acculturation, because social and cultural factors such as an ethnic group’s norms and attitudes can influence alcohol abuse.

Studies have shown that heavy drinkers put themselves at greater risk for heart disease and developing potentially fatal cardiac arrhythmias. Excessive alcohol consumption can cause higher blood pressure, increase cholesterol levels and weakened heart muscles. Studies have shown that moderate wine drinking can improve the balance of low-density lipoprotein (LDL or "bad" cholesterol) to high-density lipoprotein (HDL "good" cholesterol), which has been theorized as to clean up or remove LDL from blocking arteries. The main cause of heart attacks and the pain of angina is the lack of oxygen caused by blood clots and atheromatous plaque build up in the arteries. The alcohol in wine has anticoagulant properties that limits blood clotting by making the platelets in the blood less prone to stick together and reducing the levels of fibrin protein that binds them together.

Professional cardiology associations recommend that people who are currently nondrinkers should not start drinking alcohol.

A complex mixture of genetic and environmental factors influences the risk of the development of alcoholism. Genes that influence the metabolism of alcohol also influence the risk of alcoholism, and may be indicated by a family history of alcoholism. One paper has found that alcohol use at an early age may influence the expression of genes which increase the risk of alcohol dependence. Individuals who have a genetic disposition to alcoholism are also more likely to begin drinking at an earlier age than average. Also, a younger age of onset of drinking is associated with an increased risk of the development of alcoholism, and about 40 percent of alcoholics will drink excessively by their late adolescence. It is not entirely clear whether this association is causal, and some researchers have been known to disagree with this view.

Severe childhood trauma is also associated with a general increase in the risk of drug dependency. Lack of peer and family support is associated with an increased risk of alcoholism developing. Genetics and adolescence are associated with an increased sensitivity to the neurotoxic effects of chronic alcohol abuse. Cortical degeneration due to the neurotoxic effects increases impulsive behaviour, which may contribute to the development, persistence and severity of alcohol use disorders. There is evidence that with abstinence, there is a reversal of at least some of the alcohol induced central nervous system damage. The use of cannabis was associated with later problems with alcohol use. Alcohol use was associated with an increased probability of later use of tobacco, cannabis, and other illegal drugs.

The International Agency for Research on Cancer of the World Health Organization has classified alcohol as a Group 1 carcinogen.

There are many health hazards that are caused from drinking. When students drink too much, the alcohol affects one's brain and ability to comprehend what is going on. One such problem is alcohol poisoning. After drinking too much, the alcohol and toxins in alcoholic drinks cause complications in one's brain and respiratory system. This causes mental and physical issues in one's body and could be very dangerous for one's health. Other hazardous health issues could arise from a drug called Rohypnol, nicknamed roofies. This is a toxic drug that could potentially be slipped into one’s drink which cause one to lose sight of what one thinks and does. This will also cause complications within one's body.

Extensive epidemiological studies have demonstrated the cardioprotective effect of alcohol consumption. However the mechanism by which this occurs is not fully understood. Research has suggested several possible mechanisms, including the following.

There is a lack of medical consensus about whether moderate consumption of beer, wine, or distilled spirits has a stronger association with heart disease. Studies suggest that each is effective, with none having a clear advantage. Most researchers now believe that the most important ingredient is the alcohol itself.

The American Heart Association has reported that "More than a dozen prospective studies have demonstrated a consistent, strong, dose-response relation between increasing alcohol consumption and decreasing incidence of CHD (coronary heart disease). The data are similar in men and women in a number of different geographic and ethnic groups. Consumption of one or two drinks per day is associated with a reduction in risk of approximately 30% to 50%".

Heart disease is the largest cause of mortality in the United States and many other countries. Therefore, some physicians have suggested that patients be informed of the potential health benefits of drinking alcohol in moderation, especially if they abstain and alcohol is not contraindicated. Others, however, argue against the practice in fear that it might lead to heavy or abusive alcohol consumption. Heavy drinking is associated with a number of health and safety problems.

Acute intoxication, such as binge drinking and alcoholism, are known potent risk factors for suicide. Binge drinking is also associated with an increased risk of unplanned sex, unprotected sex, unplanned pregnancies, and an increased risk of HIV infection. 10 percent of women and 19 percent of men have reported being assaulted as a result of alcohol. Males who drink more than 35 units of alcohol per week report being physically hurt as a result of alcohol, and 15 percent report physically hurting others as a result of their drinking. Almost 16 percent of binge drinkers report being taken advantage of sexually, and 8 percent report taking advantage of another person sexually as a result of alcohol within a 1-year period. Heavy drinkers cause approximately 183,000 rapes and sexual assaults, 197,000 robberies, 661,000 aggravated assaults, and 1.7 million simple assaults each year. Binge drinking has been associated with high odds of divorce, spousal abuse, and poor job performance. Binge drinking can cause adverse effects on the body including effects on blood homeostasis and its circadian variation, cardiac rhythm, ischaemic heart disease, blood pressure, white blood cell activity, female reproductive hormone levels as well as adverse effects on the fetus. There is also evidence from animal studies that binge drinking causes brain damage. Binge drinking has been associated with lower abdominal pain in women. Ketoacidosis can occur in individuals who chronically abuse alcohol and have a recent history of binge drinking. Alcohol affects brain development quite significantly especially during adolescence when the brain is still developing. The main lobes that are involved in decision making and complex thought processes are undergoing their final development phase during adolescence and binge drinking can negatively stunt the growth of these frontal lobes.

Binge drinking occurs when students drink large amounts of alcohol in a relatively short space of time in order to feel the full effects of alcohol consumption. The National Institute of Alcohol Abuse and Alcoholism defines binge drinking as a pattern of drinking that brings a person's blood alcohol concentration, also known as BAC, to 0.08 grams percent or above. This is usually seen when men consume five or more drinks, and when women consume four or more drinks in a two-hour time period.

Young adults who participate in binge drinking experience higher rates of physical and sexual assault, and unwanted, unplanned, and unprotected sexual activity. There are also links between heavy alcohol consumption and depression.

The motivations among young students have changed as well. In recent years, more students are drinking with the intended purpose of getting drunk.

Marquis states how "Adolescent alcohol

use is not an acceptable rite of passage but a serious threat to adolescent

development and health, as the statistics related to adolescent impairment,

injury, and death attest." Research shows how an adolescent

makes the decision to consume alcohol because they are influenced by various

factors. "These factors include normal maturational changes that all

adolescents experience; genetic, psychological and social factors specific to

each adolescent and the various social and cultural environments that surround

adolescent, including their families, schools and communities". It is also

shown that early onset of alcohol intake can lead to high levels of alcohol use

in adulthood.

Alcoholism throughout adolescents is increasing yearly for a number of different reasons. These reasons include:

- Availability of alcohol

- Peer pressure

- Role model

- Television

- Anxiety or stress

Conditions of fatigue correlate positively with increased alcohol consumption.

Around 80% of Asian people (less common in Thailand, Laos and the Indian subcontinent) have a variant of the gene coding for the enzyme alcohol dehydrogenase called "ADH1B", whereas almost all Japanese, Korean and Chinese people have a variant of the gene called "ADH1C", both resulting in an alcohol dehydrogenase enzyme that converts alcohol to toxic acetaldehyde at a much higher efficiency than other gene variants (40- to 100-fold in case of ADH1B).

In about 50% of Asians, the increased acetaldehyde accumulation is worsened by another gene variant, the mitochondrial ALDH2 allele, which results in a less functional acetaldehyde dehydrogenase enzyme, responsible for the breakdown of acetaldehyde. The result is that affected people may be better at metabolizing alcohol, often not feeling the alcohol "buzz" to the same extent as others, but show far more acetaldehyde-based side effects while drinking.

Passive drinking, like passive smoking, refers to the damage done to others as a result of drinking alcoholic beverages. These include the unborn fetus and children of parents who drink excessively, drunk drivers, accidents, domestic violence and alcohol-related sexual assaults

On 2 February 2010 Eurocare, the European Alcohol Policy Alliance, organised a seminar on “The Social Cost of Alcohol : Passive drinking”. On 21 May 2010 the World Health Organization reached a consensus at the World Health Assembly on a resolution to confront the harmful use of alcohol.

A legal minimum age for the buying or consuming of alcohol is in place in many of the world's countries, typically with the intent to protect the young from alcohol-related harm. This age varies between countries; for example, the minimum legal drinking age for Australia is 18, whereas the MLDA in the United States is 21.

A normal liver detoxifies the blood of alcohol over a period of time that depends on the initial level and the patient's overall physical condition. An abnormal liver will take longer but still succeeds, provided the alcohol does not cause liver failure.

People having drunk heavily for several days or weeks may have withdrawal symptoms after the acute intoxication has subsided.

A person consuming a dangerous amount of alcohol persistently can develop memory blackouts and idiosyncratic intoxication or pathological drunkenness symptoms.

Long-term persistent consumption of excessive amounts of alcohol can cause liver damage and have other deleterious health effects.