Pulling black stools for half a month is usually not life threatening.
Pulling black stools may be related to gastrointestinal bleeding caused by peptic ulcers, inflammation, tumors and other diseases, and may also be related to taking iron-containing foods or drugs, bismuth and black foods and other reasons.
If you take iron-containing foods or drugs, under the action of intestinal bacteria can generate iron sulfide, manifesting black stool; bismuth potassium citrate, colloidal bismuth pectin and other drugs, may also lead to black stool, so pulling a black stool for half a month is generally not life-threatening.
If the phenomenon of pulling black stool for half a month, you need to go to the hospital for further examination of stool routine, gastroscopy, enteroscopy and other items to clarify the cause of the disease, under the guidance of the doctor for treatment.