WAD is typically self-limited, generally resolving without specific treatment. Oral rehydration therapy with rehydration salts is often beneficial to replace lost fluids and electrolytes. Clear, disinfected water or other liquids are routinely recommended.

Hikers who develop three or more loose stools in a 24-hour period – especially if associated with nausea, vomiting, abdominal cramps, fever, or blood in stools – should be treated by a doctor and may benefit from antibiotics, usually given for 3–5 days. Alternatively, a single dose azithromycin or levofloxacin may be prescribed. If diarrhea persists despite therapy, travelers should be evaluated and treated for possible parasitic infection.

"Cryptosporidium" can be quite dangerous to patients with compromised immune systems. Alinia (nitazoxanide) is approved by the FDA for treatment of "Cryptosporidium".

If diarrhea becomes severe (typically defined as three or more loose stools in an eight-hour period), especially if associated with nausea, vomiting, abdominal cramps, fever, or blood in stools, medical treatment should be sought. Such patients may benefit from antimicrobial therapy. A 2000 literature review found that antibiotic treatment shortens the duration and severity of TD; most reported side effects were minor, or resolved on stopping the antibiotic.

Fluoroquinolone antibiotics are the drugs of choice. Trimethoprim–sulfamethoxazole and doxycycline are no longer recommended because of high levels of resistance to these agents. Antibiotics are typically given for three to five days, but single doses of azithromycin or levofloxacin have been used. Rifaximin is approved in the U.S. for treatment of TD caused by ETEC. If diarrhea persists despite therapy, travelers should be evaluated for bacterial strains resistant to the prescribed antibiotic, possible viral or parasitic infections, bacterial or amoebic dysentery, "Giardia", helminths, or cholera.

Dysentery is managed by maintaining fluids by using oral rehydration therapy. If this treatment cannot be adequately maintained due to vomiting or the profuseness of diarrhea, hospital admission may be required for intravenous fluid replacement. In ideal situations, no antimicrobial therapy should be administered until microbiological microscopy and culture studies have established the specific infection involved. When laboratory services are not available, it may be necessary to administer a combination of drugs, including an amoebicidal drug to kill the parasite, and an antibiotic to treat any associated bacterial infection.

If shigellosis is suspected and it is not too severe, letting it run its course may be reasonable — usually less than a week. If the case is severe, antibiotics such as ciprofloxacin or TMP-SMX may be useful. However, many strains of "Shigella" are becoming resistant to common antibiotics, and effective medications are often in short supply in developing countries. If necessary, a doctor may have to reserve antibiotics for those at highest risk for death, including young children, people over 50, and anyone suffering from dehydration or malnutrition.

Amoebic dysentery is often treated with two antimicrobial drug such as metronidazole and paromomycin or iodoquinol.

Most cases of TD are mild and resolve in a few days without treatment, but severe or protracted cases may result in significant fluid loss and dangerous electrolytic imbalance. Dehydration due to diarrhea can also alter the effectiveness of medicinal and contraceptive drugs. Adequate fluid intake (oral rehydration therapy) is therefore a high priority. Commercial rehydration drinks are widely available; alternatively, purified water or other clear liquids are recommended, along with salty crackers or oral rehydration salts (available in stores and pharmacies in most countries) to replenish lost electrolytes. Carbonated water or soda, left open to allow dissipation of the carbonation, is useful when nothing else is available. In severe or protracted cases, the oversight of a medical professional is advised.

Since wilderness acquired diarrhea can be caused by insufficient hygiene, contaminated water, and (possibly) increased susceptibility from vitamin deficiency, prevention methods should address these causes.

Treatment consists mainly of replacing fluids and salts lost because of diarrhea. Replacement by mouth is satisfactory for most people, but some may need to receive fluids intravenously. Antidiarrheal drugs (such as diphenoxylate or loperamide) may prolong the infection and should not be used.

Antiemetic medications may be helpful for treating vomiting in children. Ondansetron has some utility, with a single dose being associated with less need for intravenous fluids, fewer hospitalizations, and decreased vomiting. Metoclopramide might also be helpful. However, the use of ondansetron might possibly be linked to an increased rate of return to hospital in children. The intravenous preparation of ondansetron may be given orally if clinical judgment warrants. Dimenhydrinate, while reducing vomiting, does not appear to have a significant clinical benefit.

With correct treatment, most cases of amoebic and bacterial dysentery subside within 10 days, and most individuals achieve a full recovery within two to four weeks after beginning proper treatment. If the disease is left untreated, the prognosis varies with the immune status of the individual patient and the severity of disease. Extreme dehydration can delay recovery and significantly raises the risk for serious complications.

Antibiotics should only be used in severe cases or for certain populations with mild symptoms (elderly, immunocompromised, food service industry workers, child care workers). For "Shigella"-associated diarrhea, antibiotics shorten the length of infection, but they are usually avoided in mild cases because many "Shigella" strains are becoming resistant to common antibiotics. Furthermore, effective medications are often in short supply in developing countries, which carry the majority of the disease burden from "Shigella". Antidiarrheal agents may worsen the sickness, and should be avoided.

In most cases, the disease resolves within four to eight days without antibiotics. Severe infections may last three to six weeks. Antibiotics, such as trimethoprim-sulfamethoxazole, ciprofloxacin may be given when the person is very young or very old, when the disease is severe, or when the risk of the infection spreading to other people is high. Additionally, ampicillin (but not amoxicillin) was effective in treating this disease previously, but now the first choice of drug is pivmecillinam.

Gastroenteritis is usually an acute and self-limiting disease that does not require medication. The preferred treatment in those with mild to moderate dehydration is oral rehydration therapy (ORT). For children at risk of dehydration from vomiting, taking a single dose of the anti vomiting medication metoclopramide or ondansetron, may be helpful, and butylscopolamine is useful in treating abdominal pain.

Dysentery is initially managed by maintaining fluid intake using oral rehydration therapy. If this treatment cannot be adequately maintained due to vomiting or the profuseness of diarrhea, hospital admission may be required for intravenous fluid replacement. Ideally, no antimicrobial therapy should be administered until microbiological microscopy and culture studies have established the specific infection involved. When laboratory services are not available, it may be necessary to administer a combination of drugs, including an amoebicidal drug to kill the parasite and an antibiotic to treat any associated bacterial infection.

Anyone with bloody diarrhea needs immediate medical help. Treatment often starts with an oral rehydrating solution—water mixed with salt and carbohydrates—to prevent dehydration. (Emergency relief services often distribute inexpensive packets of sugars and mineral salts that can be mixed with clean water and used to restore lifesaving fluids in dehydrated children gravely ill from dysentery.)

If "Shigella" is suspected and it is not too severe, the doctor may recommend letting it run its course—usually less than a week. The patient will be advised to replace fluids lost through diarrhea. If the infection is severe, the doctor may prescribe antibiotics, such as ciprofloxacin or TMP-SMX (Bactrim). Unfortunately, many strains of "Shigella" are becoming resistant to common antibiotics, and effective medications are often in short supply in developing countries. If necessary, a doctor may have to reserve antibiotics for those at highest risk for death, including young children, people over 50, and anyone suffering from dehydration or malnutrition.

No vaccine is available. There are several "Shigella" vaccine candidates in various stages of development that could reduce the incidence of dysentery in endemic countries, as well as in travelers suffering from traveler's diarrhea.

Electrolytes may be replenished with oral rehydration supplements (typically containing salts sodium chloride and potassium chloride).

Appropriate antibiotics, such as ceftriaxone, may be given to kill the bacteria but are not necessary in most cases. Azithromycin has been suggested to be better at treating typhoid in resistant populations than both fluoroquinolone drugs and ceftriaxone. Antibiotic resistance rates are increasing throughout the world, so health care providers should check current recommendations before choosing an antibiotic.

Treatment is supportive and based upon symptoms, with fluid and electrolyte replacement as the primary goal. Dehydration caused by diarrhea and vomiting is the most common complication. To prevent dehydration, it is important to take frequent sips of a rehydration drink (like water) or try to drink a cup of water or rehydration drink for each large, loose stool.

Dietary management of enteritis consists of starting with a clear liquid diet until vomiting and diarrhea end and then slowly introduce the BRATT diet. The BRATT diet consists of bananas, rice, applesauce, tea, and toast. It is also important to avoid foods that are high in fiber or are possibly difficult to digest.

The body can usually fight off the disease on its own. The most important factor when treating gastroenteritis is the replacement of fluids and electrolytes that are lost because of the diarrhea and vomiting.

Antibiotics will not be effective if the cause of gastroenteritis is a viral infection. Doctors usually do not recommend antidiarrheal medications (e.g., Loperamide) for gastroenteritis because they tend to prolong infection, especially in children.

Parasitic infections are difficult to treat. A number of drugs are available once the condition has been identified. Removing part of the colon or needle aspiration of abscesses in liver may be required.

Treatment for colitis-X usually does not save the horse. The prognosis is average to poor, and mortality is 90% to 100%. However, treatments are available, and one famous horse that survived colitis-X was U.S. Triple Crown winner Seattle Slew, that survived colitis-X in 1978 and went on to race as a four-year-old.

Large amounts of intravenous fluids are needed to counter the severe dehydration, and electrolyte replacement is often necessary. Flunixin meglumine (Banamine) may help block the effects of toxemia. Mortality rate has been theorized to fall to 75% if treatment is prompt and aggressive, including administration of not only fluids and electrolytes, but also blood plasma, anti-inflammatory and analgesic drugs, and antibiotics. Preventing dehydration is extremely important. Nutrition is also important. Either parenteral or normal feeding can be used to support the stressed metabolism of the sick horse. Finally, the use of probiotics is considered beneficial in the restoration of the normal intestinal flora. The probiotics most often used for this purpose contain "Lactobacillus" and "Bifidobacterium".

Antibiotic treatment only has a marginal effect on the duration of symptoms, and its use is not recommended except in high-risk patients with clinical complications.

Erythromycin can be used in children, and tetracycline in adults. Some studies show, however, that erythromycin rapidly eliminates "Campylobacter" from the stool without affecting the duration of illness. Nevertheless, children with dysentery due to "C. jejuni" benefit from early treatment with erythromycin. Treatment with antibiotics, therefore, depends on the severity of symptoms. Quinolones are effective if the organism is sensitive, but high rates of quinolone use in livestock means that quinolones are now largely ineffective.

Antimotility agents, such as loperamide, can lead to prolonged illness or intestinal perforation in any invasive diarrhea, and should be avoided. Trimethoprim/sulfamethoxazole and ampicillin are ineffective against "Campylobacter".

In many cases of diarrhea, replacing lost fluid and salts is the only treatment needed. This is usually by mouth – oral rehydration therapy – or, in severe cases, intravenously. Diet restrictions such as the BRAT diet are no longer recommended. Research does not support the limiting of milk to children as doing so has no effect on duration of diarrhea. To the contrary, WHO recommends that children with diarrhea continue to eat as sufficient nutrients are usually still absorbed to support continued growth and weight gain, and that continuing to eat also speeds up recovery of normal intestinal functioning. CDC recommends that children and adults with cholera also continue to eat.

Medications such as loperamide (Imodium) and bismuth subsalicylate may be beneficial; however they may be contraindicated in certain situations.

Oral rehydration solution (ORS) (a slightly sweetened and salty water) can be used to prevent dehydration. Standard home solutions such as salted rice water, salted yogurt drinks, vegetable and chicken soups with salt can be given. Home solutions such as water in which cereal has been cooked, unsalted soup, green coconut water, weak tea (unsweetened), and unsweetened fresh fruit juices can have from half a teaspoon to full teaspoon of salt (from one-and-a-half to three grams) added per liter. Clean plain water can also be one of several fluids given. There are commercial solutions such as Pedialyte, and relief agencies such as UNICEF widely distribute packets of salts and sugar. A WHO publication for physicians recommends a homemade ORS consisting of one liter water with one teaspoon salt (3 grams) and two tablespoons sugar (18 grams) added (approximately the "taste of tears"). Rehydration Project recommends adding the same amount of sugar but only one-half a teaspoon of salt, stating that this more dilute approach is less risky with very little loss of effectiveness. Both agree that drinks with too much sugar or salt can make dehydration worse.

Appropriate amounts of supplemental zinc and potassium should be added if available. But the availability of these should not delay rehydration. As WHO points out, the most important thing is to begin preventing dehydration as early as possible. In another example of prompt ORS hopefully preventing dehydration, CDC recommends for the treatment of cholera continuing to give Oral Rehydration Solution during travel to medical treatment.

Vomiting often occurs during the first hour or two of treatment with ORS, especially if a child drinks the solution too quickly, but this seldom prevents successful rehydration since most of the fluid is still absorbed. WHO recommends that if a child vomits, to wait five or ten minutes and then start to give the solution again more slowly.

Drinks especially high in simple sugars, such as soft drinks and fruit juices, are not recommended in children under 5 years of age as they may "increase" dehydration. A too rich solution in the gut draws water from the rest of the body, just as if the person were to drink sea water. Plain water may be used if more specific and effective ORT preparations are unavailable or are not palatable. Additionally, a mix of both plain water and drinks perhaps too rich in sugar and salt can alternatively be given to the same person, with the goal of providing a medium amount of sodium overall. A nasogastric tube can be used in young children to administer fluids if warranted.

"E. histolytica" infections occur in both the intestine and (in people with symptoms) in tissue of the intestine and/or liver. As a result, two different classes of drugs are needed to treat the infection, one for each location. Such anti-amoebic drugs are known as amoebicides.

Antibiotic treatments for one to three days shorten the course of the disease and reduce the severity of the symptoms. Use of antibiotics also reduces fluid requirements. People will recover without them, however, if sufficient hydration is maintained. The World Health Organization only recommends antibiotics in those with severe dehydration.

Doxycycline is typically used first line, although some strains of "V. cholerae" have shown resistance. Testing for resistance during an outbreak can help determine appropriate future choices. Other antibiotics proven to be effective include cotrimoxazole, erythromycin, tetracycline, chloramphenicol, and furazolidone. Fluoroquinolones, such as ciprofloxacin, also may be used, but resistance has been reported.

Antibiotics improve outcomes in those who are both severely and not severely dehydrated. Azithromycin and tetracycline may work better than doxycycline or ciprofloxacin.

To date, no licensed vaccines specifically target ETEC, though several are in various stages of development. Studies indicate that protective immunity to ETEC develops after natural or experimental infection, suggesting that vaccine-induced ETEC immunity should be feasible and could be an effective preventive strategy. Prevention through vaccination is a critical part of the strategy to reduce the incidence and severity of diarrheal disease due to ETEC, particularly among children in low-resource settings. The development of a vaccine against this infection has been hampered by technical constraints, insufficient support for coordination, and a lack of market forces for research and development. Most vaccine development efforts are taking place in the public sector or as research programs within biotechnology companies. ETEC is a longstanding priority and target for vaccine development for the World Health Organization.

Treatment for ETEC infection includes rehydration therapy and antibiotics, although ETEC is frequently resistant to common antibiotics. Improved sanitation is also key. Since the transmission of this bacterium is fecal contamination of food and water supplies, one way to prevent infection is by improving public and private health facilities. Another simple prevention of infection is by drinking factory bottled water—this is especially important for travelers and traveling military—though it may not be feasible in developing countries, which carry the greatest disease burden.

The infection is usually self-limiting, and in most cases, symptomatic treatment by liquid and electrolyte replacement is enough in human infections.

The most common error in caring for patients with cholera is to underestimate the speed

and volume of fluids required. In most cases, cholera can be successfully treated with oral rehydration therapy (ORT), which is highly effective, safe, and simple to administer. Rice-based solutions are preferred to glucose-based ones due to greater efficiency. In severe cases with significant dehydration, intravenous rehydration may be necessary. Ringer's lactate is the preferred solution, often with added potassium. Large volumes and continued replacement until diarrhea has subsided may be needed. Ten percent of a person's body weight in fluid may need to be given in the first two to four hours. This method was first tried on a mass scale during the Bangladesh Liberation War, and was found to have much success. Despite widespread beliefs, fruit juices and commercial fizzy drinks like cola, are not ideal for rehydration of people with serious infections of the intestines, and their excessive sugar content may even harm water uptake.

If commercially produced oral rehydration solutions are too expensive or difficult to obtain, solutions can be made. One such recipe calls for 1 liter of boiled water, 1/2 teaspoon of salt, 6 teaspoons of sugar, and added mashed banana for potassium and to improve taste.

The FDA has published guidelines to help reduce the chance of food-borne salmonellosis. Food must be cooked to 68–72 °C (145–160 °F), and liquids such as soups or gravies must be boiled. Freezing kills some "Salmonella", but it is not sufficient to reliably reduce them below infectious levels. While "Salmonella" is usually heat-sensitive, it does acquire heat resistance in high-fat environments such as peanut butter.

Depending on the cause of the inflammation, symptoms may last from one day to more than a week.

Gastroenteritis caused by viruses may last one to two days. Most people recover easily from a short episode of vomiting and diarrhea by drinking clear fluids to replace the fluid that was lost and then gradually progressing to a normal diet. But for others, especially infants and the elderly, the loss of bodily fluid with gastroenteritis can cause dehydration, which can be a life-threatening illness unless it is treated and fluids in the body are replaced.