Why Causes Sour Smelling Poop?

Inside your digestive system, beneficial bacteria work together to break down the food you eat. During digestion, these bacteria produce various chemicals, including acids. When you change your diet or the balance of bacteria in your digestive system shifts, more acids may be produced—giving your stool a sour smell. For example, eating lots of fruits, yogurt, or fermented foods can alter this acid balance. When there's a slight disruption in normal gut bacteria—known as dysbiosis—the increased production of acidic compounds can make your stool smell sour. If the sour smell is persistent or associated with other symptoms like abdominal pain or changes in bowel habits, it’s a good idea to talk with a healthcare provider so they can better evaluate for any underlying digestive issues.