Some supplements, like chondroitin, fish oil, and iron, may lead to unwanted side effects, including smelly stool (poop). Supplements that can make your poop smell include chondroitin, glucosamine ...

Fish oil supplements may cause steatorrhea, which can make poop smell fishy and appear oily. Steatorrhea is the presence of fatty oils in your stool. It occurs when your body cannot break down or ...