Dark foul-smelling stool occurs when digested blood or undigested food alters stool color and odor. It may indicate minor digestive issues or serious conditions like internal bleeding.
Stool gets its normal brown color from bile, a digestive fluid produced by your liver. When blood from your upper digestive tract bleeds, it gets broken down by stomach acid, turning black and giving stool its dark color. Undigested food, especially certain vegetables and supplements, can also cause discoloration.
The foul smell comes from bacteria breaking down food in your intestines. Some foods, like eggs or meat, create stronger odors than others. Certain medical conditions can also increase stool odor.
Dark foul-smelling stool has several possible causes:
Consult a doctor if:
These could indicate serious conditions requiring medical attention. According to the Mayo Clinic, persistent dark stools can sometimes signal gastrointestinal bleeding.
Many people assume dark stool always means internal bleeding. However, harmless foods and supplements can also cause discoloration. The key difference is consistency - bleeding-related dark stool tends to be tarry and sticky, while food-related discoloration usually appears normal in texture.
Another misconception is that foul-smelling stool always indicates infection. While infections can cause bad odors, many other factors contribute to stool smell, including diet and digestive health.
Understanding what makes your stool dark can help you recognize potential health issues early. When in doubt, always consult a medical professional for personalized advice.