** Thanks for contacting HCM with your health concern 1. Diarrhea in IIIrd Trimester is normal [more common] and also sometime indicate upcoming labor or preterm labor but certain other conditions/causes which have to looked upon are: i. As the stool is suggestive of infection thus one has to exclude possibilities like: food poisoning [gastroenteritis], stomach flu, inflammatory bowel disease and irritable bowel syndrome [maternal gastrointestinal conditions] PS. prenatal vitamins [iron],hormonal changes being others 2. Although diarrhea is not harmful to the baby, but severe [as in your case] can dehydrate you and hamper the blood flow to the fetus, so before opting for any OTC [over the counter] medication /callcontact your attending GYNOB doctor immediately for further treatment and management 3. Till then FDA approved Imodium tablet can be taken safely and opt for whole wheat toast [without butter],brown rice,banana, vegetables soup, potatoes, carrots,yogurt, and Avoid carbonated/caffeinated drinks, fried items, spices, sugar and dry fruits