Taking anti-inflammatory drugs to consider the upper gastrointestinal bleeding, most commonly seen in reflux esophagitis, chronic gastritis, peptic ulcer, gastric cancer and so on. 1. Reflux esophagitis: due to the inflammation of the esophageal mucosa, taking anti-inflammatory drugs stimulates the esophageal mucosa to aggravate the symptoms, which causes bleeding, and the blood is discharged into the intestine for a longer period of time, resulting in black stools. 2. Chronic gastritis: gastric mucosa inflammation and erosion, taking anti-inflammatory drugs to further stimulate the gastric mucosa caused by bleeding, blood in the intestinal tract and feces mix, so the stool becomes black, accompanied by acid reflux, nausea, stomach pain and other symptoms. 3. Peptic ulcer: the protective barrier of gastric mucosa is damaged and there is ulcer surface, after taking anti-inflammatory drugs, the ulcer surface is stimulated and causes bleeding, the blood is oxidized and formed into sulfide in the intestinal tract, so the stool becomes black, accompanied by acid reflux, heartburn, nausea, stomach pain and other symptoms; long-term use of non-steroidal anti-inflammatory drugs can lead to the damage of gastric mucous membrane barrier, resulting in peptic ulcer. 4. Gastric cancer: cancer cells infiltrate the stomach tissues and stimulate the gastric mucosa after taking anti-inflammatory drugs, resulting in black stools, accompanied by symptoms such as emaciation and anemia. If you take anti-inflammatory drugs and your stool turns black, it is recommended to consult a doctor in time to find out the cause of the disease and follow the doctor’s prescription.