Farting with putrid smell may be caused by ulcerative colitis, indigestion, intestinal flora disorders, digestive tract tumors. 1. Ulcerative colitis: this kind of people can have increased farting with putrid odor, and also can have symptoms such as anxiousness (discomfort in the lower abdomen, wanting to defecate very much, and a feeling of incomplete defecation after defecation), mucus, pus and blood stool, abdominal pain, diarrhea and so on. 2. Dyspepsia: It is mostly caused by too much food, food accumulation, decreased digestive ability of gastrointestinal tract which cannot digest the ingested food, and the food accumulation through fermentation can result in increased gas production and putrid odor. 3. Disorders of intestinal flora: when food passes through the intestines, due to the disorders of intestinal flora, resulting in malabsorption, the fermentation of food can appear putrid odor and increased gas production. 4. Tumor of digestive tract: patients with tumor of digestive tract have decreased digestive ability and the tumor of intestinal tract may cause intestinal obstruction, and the accumulation and fermentation of food in the intestinal tract will produce gas with putrid smell. For serious cases, it is recommended to go to the hospital in time.