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.

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.

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.

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.

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".

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

Antibiotics are not usually used for gastroenteritis, although they are sometimes recommended if symptoms are particularly severe or if a susceptible bacterial cause is isolated or suspected. If antibiotics are to be employed, a macrolide (such as azithromycin) is preferred over a fluoroquinolone due to higher rates of resistance to the latter. Pseudomembranous colitis, usually caused by antibiotic use, is managed by discontinuing the causative agent and treating it with either metronidazole or vancomycin. Bacteria and protozoans that are amenable to treatment include "Shigella" "Salmonella typhi", and "Giardia" species. In those with "Giardia" species or "Entamoeba histolytica", tinidazole treatment is recommended and superior to metronidazole. The World Health Organization (WHO) recommends the use of antibiotics in young children who have both bloody diarrhea and fever.

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.

Symptomatic treatment primarily involves fluid rehydration, electrolyte replacement (sodium, potassium, bicarbonate, and glucose), and antimotility agents (e.g., loperamide). Supplemental zinc may improve symptoms, particularly in recurrent or persistent infections or in others at risk for zinc deficiency.

Immunocompetent individuals with cryptosporidiosis typically suffer a short (i.e., duration of less than 2 weeks) self-limiting course of diarrhea that may require symptomatic treatment and ends with spontaneous recovery; in some circumstances, antiparasitic medication may be required (e.g., recurrent, severe, or persistent symptoms); however reinfection frequently occurs.

, nitazoxanide is the only antiparasitic drug treatment with proven efficacy for cryptosporidiosis in immunocompetent individuals; however, it lacks efficacy in severely immunocompromised patients. Certain agents such as paromomycin and azithromycin are sometimes used as well, but they only have partial efficacy.

The most efficient treatment in breeding flocks or laying hens is individual intramuscular injections of a long-acting tetracycline, with the same antibiotic in drinking water, simultaneously. The mortality and clinical signs will stop within one week, but the bacteria might remain present in the flock.

The two classes of antiviral drugs used against influenza are neuraminidase inhibitors (oseltamivir and zanamivir) and M2 protein inhibitors (adamantane derivatives).

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.

Overall the benefits of neuraminidase inhibitors in those who are otherwise healthy do not appear to be greater than the risks. There does not appear to be any benefit in those with other health problems. In those believed to have the flu, they decreased the length of time symptoms were present by slightly less than a day but did not appear to affect the risk of complications such as needing hospitalization or pneumonia. Previous to 2013 the benefits were unclear as the manufacturer (Roche) refused to release trial data for independent analysis. Increasingly prevalent resistance to neuraminidase inhibitors has led to researchers to seek alternative antiviral drugs with different mechanisms of action.

As the infection is usually transmitted into humans through animal bites, antibiotics usually treat the infection, but medical attention should be sought if the wound is severely swelling. Pasteurellosis is usually treated with high-dose penicillin if severe. Either tetracycline or chloramphenicol provides an alternative in beta-lactam-intolerant patients. However, it is most important to treat the wound.

Antibiotics such as tetracyclines, rifampin, and the aminoglycosides streptomycin and gentamicin are effective against "Brucella" bacteria. However, the use of more than one antibiotic is needed for several weeks, because the bacteria incubate within cells.

Surveillance using serological tests, as well as tests on milk like the milk ring test, can be used for screening and play an important role in campaigns to eliminate the disease. Also, individual animal testing both for trade and for disease-control purposes is practiced. In endemic areas, vaccination is often used to reduce the incidence of infection. An animal vaccine is available that uses modified live bacteria. The World Organisation for Animal Health "Manual of Diagnostic Test and Vaccines for Terrestrial Animals" provides detailed guidance on the production of vaccines. As the disease is closer to being eliminated, a test and stamping out program is required to completely eliminate it.

The gold standard treatment for adults is daily intramuscular injections of streptomycin 1 g for 14 days and oral doxycycline 100 mg twice daily for 45 days (concurrently). Gentamicin 5 mg/kg by intramuscular injection once daily for seven days is an acceptable substitute when streptomycin is not available or contraindicated. Another widely used regimen is doxycycline plus rifampin twice daily for at least six weeks. This regimen has the advantage of oral administration. A triple therapy of doxycycline, with rifampin and co-trimoxazole, has been used successfully to treat neurobrucellosis.

Doxycycline is able to cross the blood–brain barrier, but requires the addition of two other drugs to prevent relapse. Ciprofloxacin and co-trimoxazole therapy is associated with an unacceptably high rate of relapse. In brucellic endocarditis, surgery is required for an optimal outcome. Even with optimal antibrucellic therapy, relapses still occur in 5 to 10% of patients with Malta fever.

The main way of preventing brucellosis is by using fastidious hygiene in producing raw milk products, or by pasteurizing all milk that is to be ingested by human beings, either in its unaltered form or as a derivate, such as cheese.

Treatment depends on many factors, such as the age of horse, severity of symptoms and duration of infection. As long a horse is eating and drinking, the infection must run its course, much like a common cold virus. Over time a horse will build up enough antibodies to overtake and fight the disease. Other treatment options can be applying heat packs to abscesses to help draw it to the surface and using drawing salves such as Ichthammol. A blood test or bacterial cultures can be taken to confirm the horse is fighting Pigeon Fever. Anti-inflammatory such as phenylbutazone can be used to ease pain and help control swelling. Treating Pigeon Fever with antibiotics is not normally recommended for external abscesses since it is a strong bacterium that takes extended treatment to kill off and to ensure it does not return stronger. However, if the abscesses are internal then antibiotics may be needed. Consulting a veterinarian for treatment is recommended. Making the horse comfortable, ensuring the horse has good food supply and quality hay will help the horse keep their immune system strong to fight off the infection. Once the abscess breaks or pops, it will drain for a week or two. During this time keeping the area clean, applying hot packs or drawing salves will help remove the pus that has gathered in the abscess.

Zinc supplementation may benefit children over six months old with diarrhea in areas with high rates of malnourishment or zinc deficiency. This supports the World Health Organization guidelines for zinc, but not in the very young.

Probiotics reduce the duration of symptoms by one day and reduced the chances of symptoms lasting longer than four days by 60%. The probiotic lactobacillus can help prevent antibiotic-associated diarrhea in adults but possibly not children. For those with lactose intolerance, taking digestive enzymes containing lactase when consuming dairy products often improves symptoms.

While antibiotics are beneficial in certain types of acute diarrhea, they are usually not used except in specific situations. There are concerns that antibiotics may increase the risk of hemolytic uremic syndrome in people infected with . In resource-poor countries, treatment with antibiotics may be beneficial. However, some bacteria are developing antibiotic resistance, particularly "Shigella". Antibiotics can also cause diarrhea, and antibiotic-associated diarrhea is the most common adverse effect of treatment with general antibiotics.

While bismuth compounds (Pepto-Bismol) decreased the number of bowel movements in those with travelers' diarrhea, they do not decrease the length of illness. Anti-motility agents like loperamide are also effective at reducing the number of stools but not the duration of disease. These agents should only be used if bloody diarrhea is not present.

Bile acid sequestrants such as cholestyramine can be effective in chronic diarrhea due to bile acid malabsorption. Therapeutic trials of these drugs are indicated in chronic diarrhea if bile acid malabsorption cannot be diagnosed with a specific test, such as SeHCAT retention.

El Tor is the name given to a particular strain of the bacterium "Vibrio cholerae", the causative agent of cholera. Also known as "V. cholera" biotype eltor, it has been the dominant strain in the seventh global pandemic. It is distinguished from the classic strain at a genetic level, although both are in the serogroup O1 and both contain Inaba, Ogawa and Hikojima serotypes. It is also distinguished from classic biotypes by the production of hemolysins.

When infection attacks the body, "anti-infective" drugs can suppress the infection. Several broad types of anti-infective drugs exist, depending on the type of organism targeted; they include antibacterial (antibiotic; including antitubercular), antiviral, antifungal and antiparasitic (including antiprotozoal and antihelminthic) agents. Depending on the severity and the type of infection, the antibiotic may be given by mouth or by injection, or may be applied topically. Severe infections of the brain are usually treated with intravenous antibiotics. Sometimes, multiple antibiotics are used in case there is resistance to one antibiotic. Antibiotics only work for bacteria and do not affect viruses. Antibiotics work by slowing down the multiplication of bacteria or killing the bacteria. The most common classes of antibiotics used in medicine include penicillin, cephalosporins, aminoglycosides, macrolides, quinolones and tetracyclines.

Not all infections require treatment, and for many self-limiting infections the treatment may cause more side-effects than benefits. Antimicrobial stewardship is the concept that healthcare providers should treat an infection with an antimicrobial that specifically works well for the target pathogen for the shortest amount of time and to only treat when there is a known or highly suspected pathogen that will respond to the medication.

If a person becomes sick with swine flu, antiviral drugs can make the illness milder and make the patient feel better faster. They may also prevent serious flu complications. For treatment, antiviral drugs work best if started soon after getting sick (within two days of symptoms). Beside antivirals, supportive care at home or in a hospital focuses on controlling fevers, relieving pain and maintaining fluid balance, as well as identifying and treating any secondary infections or other medical problems. The U.S. Centers for Disease Control and Prevention recommends the use of oseltamivir (Tamiflu) or zanamivir (Relenza) for the treatment and/or prevention of infection with swine influenza viruses; however, the majority of people infected with the virus make a full recovery without requiring medical attention or antiviral drugs. The virus isolated in the 2009 outbreak have been found resistant to amantadine and rimantadine.

In the U.S., on April 27, 2009, the FDA issued Emergency Use Authorizations to make available Relenza and Tamiflu antiviral drugs to treat the swine influenza virus in cases for which they are currently unapproved. The agency issued these EUAs to allow treatment of patients younger than the current approval allows and to allow the widespread distribution of the drugs, including by volunteers.

As swine influenza is rarely fatal to pigs, little treatment beyond rest and supportive care is required. Instead, veterinary efforts are focused on preventing the spread of the virus throughout the farm, or to other farms. Vaccination and animal management techniques are most important in these efforts. Antibiotics are also used to treat this disease, which although they have no effect against the influenza virus, do help prevent bacterial pneumonia and other secondary infections in influenza-weakened herds.

Fowl cholera is also called avian cholera, avian pasteurellosis, avian hemorrhagic septicemia.

It is the most common pasteurellosis of poultry. As the causative agent is "Pasteurella multocida", it is considered as a zoonosis.

Adult birds and old chickens are more susceptible. In parental flocks, cocks are far more susceptible than hens.

Besides chickens, the disease also concerns turkeys, ducks, geese, raptors, and canaries. Turkeys are particularly sensitive, with mortality ranging to 65%.

The recognition of this pathological condition is of ever increasing importance for differential diagnosis with avian influenza.

Because "B. suis" is facultative and intracellular, and is able to adapt to environmental conditions in the macrophage, treatment failure and relapse rates are high. The only effective way to control and eradicate zoonosis is by vaccination of all susceptible hosts and elmination of infected animals. The "Brucella abortus" (rough LPS "Brucella") vaccine, developed for bovine brucellosis and licensed by the USDA Animal Plant Health Inspection Service, has shown protection for some swine and is also effective against "B. suis" infection, but currently no approved vaccine for swine brucellosis is available.