Smelly farts are not necessarily bad, but may be caused by poor diet, gastrointestinal dysfunction, colon cancer and other reasons. 1. Poor dietary habits: often eating foods that are easy to produce too much gas, such as onions, ginger, beans, yogurt, etc., can lead to smelly farts, which is not a disease, not a bad health, and it is enough to pay attention to improving the dietary habits. 2. Gastrointestinal dysfunction: It is a common digestive disorder caused by various reasons of gastrointestinal dysfunction, which may result in abdominal pain, bloating, diarrhea, constipation, and farting. 3. Colon cancer: it is a common malignant tumor of the digestive tract, which mostly occurs in middle-aged people with family history and alcoholism, and the patients’ farting increases and is often foul-smelling. There may be other reasons for farting all the time, so you can go to the hospital for examination to clarify the situation and follow the doctor’s instructions for standardized treatment.