If your diarrhoea is uncomplicated and goes away within a few days, your doctor is unlikely to prescribe any treatment for your gastrointestinal (GI) upset. In healthy people, most bacterial infections of the GI tract resolve by themselves. In some cases, antibiotics actually prolong the infection and may lead to carrying the organisms for months (carrier state). Patients with underlying diseases that impair the immune response, such as cancer or HIV, may be treated with antibiotics since they cannot clear the infection on their own. If the diarrhoea is severe, bloody, includes mucus and/or has lasted for more than three or four days, then your doctor will often request tests to identify the cause of your diarrhoea and treat it accordingly. This is especially true if you have been abroad or if family members, close acquaintances or co-workers are also ill.
For viral infections and many pathogenic bacterial infections, the main treatment is to make sure that the patient replaces lost fluids and electrolytes. Infants and those with severe dehydration may not be able to drink enough to rehydrate themselves and may have to be taken into hospital for a short period of time. Your doctor will monitor your health, give you advice on preventing the spread of the infection, and watch for any complications.
Most parasitic infections are treated with medicine, although some may resolve on their own. With some bacterial and parasitic infections, your doctor may treat the entire family even if only one member is obviously affected. There is currently no effective treatment for Cryptosporidium. Most people with healthy immune systems will get rid of this infection, but some with poor immune systems (such as those with HIV/AIDS or organ transplantation) may develop a chronic infection.
Talk to your pharmacist before taking an over-the-counter anti-diarrhoea medicine. They relieve symptoms of acute (severe) diarrhoea and can be useful to reduce discomfort and social disruption. Do not take them if there is blood in your stool or you have a raised temperature. Never give anti-diarrhoea medicines to a child. Diarrhoea is one of the methods your body uses to help get rid of the infection. If you slow down or prevent this from happening by taking an anti-diarrhoea medicine you can prolong the time that you are ill.
For diarrhoea caused by a food intolerance such as lactose intolerance, treatment involves avoidance of the cause. A diagnosis of coeliac disease requires avoidance of foods containing gluten.