I have mouth ulcers and watery poo. what should i do?

Possible colitis: This may relate to colitis. An evaluation with a gastrointestinal specialist is in order.

Stress: Oral ulcers can occur when your system is under stress. Since you have diarrhea your digestive system is involved and could cause you to be run down. Diarrhea is caused by a number of things, including intestinal diseases, the flu, bad drinking water, food poisoning, greasy food...The list is almost endless. The good news is that there is really nothing to worry about unless it occurs often.

Watery Poo: Could be colitis. Consult your pcp for assessment & referral to a gastroenterologist.

Possibly Candidaisis: Candida albicans is a type of yeast organism. Usually an overgrowth of yeast can happen after the use of antibiotic. You can do this simple test found in: http://www.Candidasupport.Org/test_saliva.Html or your doctor can order a lab. Test.