I took 3 doses of pepto on monday. I've not taken any since but I still am having stomachaches/diarrea and now it is black colored stool?

Pepto Problems. Pepto bismol (bismuth subsalicylate) contains an aspirin-like compound that can irritate your stomach with repeated use. The bismuth also causes the stool to darken intensely. Pasty black foul smelling stools could indicated bleeding in the upper digestive tract. Stop the pepto, and check with your physician. If you're still having diarrhea several days into this situation you may have another problem to be checked.
Pepto bismol (bismuth subsalicylate) Pepto bismol (bismuth subsalicylate) turns the stool black. Do not worry. This is normal. If xrays are taken it also shows up as bright sparklies on the sray too!
1/20. Pepto can cause dark colored stools, however this should be checked asap by your primary care physician.