Lomotil is a brand of medication for a combination of diphenoxylate and atropine. In the U.S. it is only available by prescription, although in some European countries it is available as a pharmacist only product for diarrhea. Diphenoxylate is an opioid anti-diarrheal that slows down bowel movement during a diarrhea episode, but the anti-cholinergic of atropine makes Lomotil undesirable as a drug of abuse, so it has little recreational value.

Lomotil dosage for diarrhea is usually 2 tablets of the 2.5/0.025 mg lomotil dosage up to four times a day when needed. Some patients with a colostomy or ileostomy use this medication at a lower Lomotil dosage, typically just 2 tablets once daily. Lomotil is not recommended for pregnant women, and it is not for children. Children who have diarrhea might be suffering from a rotavirus or other conditions, using anti-diarrheal may prevent the expulsion of the virus and prolong the illness.

Medications to treat diarrhea are not recommended for children to use, children usually have acute symptoms and they generally resolve after the acute illness has resolved. Children suffer from diarrhea should be constantly rehydrated using oral electrolyte solution, and they may require medical attention if the diarrhea persist for more than a few days or if they develop signs of significant dehydration such as markedly reduced urine output, lethargy and dry mouth. Adults should rehydrate themselves when having diarrhea also, as dehydration may cause electrolyte disturbances, which may lead to problems such as acute renal dysfunction, hypotension, and even cardiac arrhythmias.