Why does feaces smell?

The smell of feces is due to the presence of volatile organic compounds (VOCs) that are produced by the anaerobic bacteria that break down the food we eat. These VOCs include hydrogen sulfide, methane, and ammonia, which all have a strong and unpleasant odor. The composition of the VOCs in feces can vary depending on the diet, health, and medications of the individual. Feces also contain a variety of other compounds, such as bile pigments, fats, and proteins, which contribute to its overall smell.