Black stools during defecation are usually caused by various reasons such as diet, medication, and gastrointestinal bleeding, and can be treated according to symptoms.

1. Diet: If a patient eats dark-colored foods, meats, animal blood products, and other foods in daily life, it may affect the color of feces, usually causing no special concern.

2. Medication: Some patients take traditional Chinese medicine or drugs containing bismuth, iron, etc., such as colloidal bismuth subgluconate capsules, metoprolol tartrate tablets, potassium citrate granules, and other drugs, which can affect the color of feces, causing it to be black and lack luster, usually requiring no special treatment.

3. Gastrointestinal bleeding: If a patient has gastrointestinal diseases that cause bleeding, black stools may occur, and it is necessary to go to a regular medical institution’s Department of Gastroenterology for examination in a timely manner.