Question: what is the best over the counter medicine for nausea and diarrhea?
Answer: Bismuth subsalicylate(2 brand names: Kaopectate, Pepto-Bismol). This medicine may help treat some types of nausea and vomiting, such as from gastroenteritis (stomach flu). It's also used for upset stomach and as an antidiarrheal (medicine to treat diarrhea).