why do farts stink

Farts usually stink because bacteria in your gut make tiny amounts of sulfur‑containing gases (like hydrogen sulfide) while breaking down food, and those sulfur gases have a strong rotten‑egg smell. What you eat, how your gut bacteria are balanced, and issues like food intolerance or constipation can all change how intense that odor is.

Quick Scoop

• Most of the gas you pass is actually odorless (mainly nitrogen, carbon dioxide, hydrogen, and methane), but about 1% contains smelly sulfur compounds that your nose really notices.

• Gut bacteria ferment foods—especially those rich in sulfur (like some proteins and cruciferous veggies)—and produce hydrogen sulfide, which smells like rotten eggs.

• Extra‑stinky farts can be linked to things like high‑sulfur diets, food intolerances (for example, lactose intolerance), constipation, or gut conditions such as celiac disease or irritable bowel syndrome, though in many people it’s completely normal.

If gas is constantly very foul‑smelling and comes with pain, weight loss, blood in stool, or big changes in bowel habits, a healthcare professional should check for underlying digestive problems.

Information gathered from public forums or data available on the internet and portrayed here.