If your bowel movements have started to smell like fish, it could also potentially mean that you’ve developed a bacterial infection, explains Statcare Urgent and Walk-In Medical Clinic. Helicobacter pylori is one such bacteria that is usually seen in connection with ulcers in the stomach or small intestine (per Mayo Clinic). Fishy-smelling poops can also be a symptom of a Campylobacter bacterial infection, which can be contracted through ingestion of contaminated, raw, or undercooked poultry, according to the U.S. Centers for Disease Control and Prevention (CDC). Bacterial vaginosis, an infection that occurs due to an imbalance of natural bacteria in the vagina, may alternatively be the reason behind a fishy bowel movement.
Those with certain health conditions, such as celiac disease or other nutrient malabsorption issues, may also notice stool with a particularly pungent, fishy smell. Estimated to affect as many as 1 in every 133 people in the U.S., celiac disease occurs when gluten triggers the immune system to attack the lining of the small intestine, thereby preventing the body from absorbing necessary nutrients (per Johns Hopkins Medicine).