What to do if i have black stools, what does it mean?

Nothing or something: Many things turn stool black - like iron pills or bismuth (pepto bismal). So, unless it is a continuing problem, don't worry. However, blood from the upper intestine - stomach ulcer, polyp, inflammation does cause the stool to be black. If it is a continuing problem, see a doctor. Tests like an upper GI series or an upper endoscopy can easily detect a problem. Peter wilk, md.