Can taking omeprazole cause black stools?
Disease description:
The patient recently experienced a recurrence of gastric ulcer, and the doctor prescribed a new course of omeprazole. After taking the medication, the patient developed black stool the same evening. I would like to consult the doctor whether this was caused by taking omeprazole.
Doctor's answer (1)
Dr. Shen Yonghua
In most cases, taking omeprazole does not cause black stools.
Omeprazole is commonly used to treat conditions caused by excess stomach acid, such as gastric ulcers, duodenal ulcers, and gastroesophageal reflux disease (GERD). In most cases, taking omeprazole does not cause black stools. Black stool, medically referred to as "tarry stool," is dark and shiny in appearance and is usually associated with gastrointestinal bleeding. The primary function of omeprazole is to inhibit gastric acid secretion, thereby protecting the gastric mucosa and reducing the risk of ulcers and bleeding. If a patient taking omeprazole develops black stool, it is more likely due to an underlying condition such as an ulcer in the stomach or duodenum that has not fully healed, or inadequate suppression of gastric acid secretion by the medication, leading to bleeding.
In some rare cases, omeprazole may contribute to gastrointestinal bleeding, which can secondarily lead to black stools. However, such occurrences are relatively uncommon and may be related to other medications, foods (such as iron or bismuth preparations), or underlying medical conditions. If black stools appear during treatment with omeprazole, prompt medical evaluation is recommended.
