Generally, ranitidine can cause black stools, which is a normal adverse drug reaction. Ranitidine, a histamine Hâ‚‚ receptor blocker, can significantly inhibit basal and nocturnal gastric acid secretion in healthy people and ulcer patients, and also has a certain inhibitory effect on pepsinogen secretion. It is mainly used to relieve stomach pain, heartburn sensation, acid reflux and other symptoms caused by excessive gastric acid, and can also be used to treat gastric and duodenal ulcers, reflux esophagitis, gastritis, and other high gastric acid secretion diseases. Ranitidine can also be used to prevent stress ulcers, stress hemorrhage, etc. It is contraindicated for those who are allergic to the product, children under 8 years of age, pregnant and lactating women, and patients with acute porphyria; use with caution in renal insufficiency, hepatic insufficiency, and the elderly. Taking Ranitidine, black stools, nausea, vomiting, skin rash, fatigue, headache, insomnia, black tongue, etc., is an adverse reaction of the drug, and can gradually disappear after stopping the drug. It is recommended to use under the guidance of a doctor and not to take the drug without authorization.