If there's no obvious reason for a black stool (such as food, a supplement, or a medication like Pepto-bismol), it could be time to look for blood in the stool. 1  A variety of medical reasons can cause black stools that are also tarry with a foul smell.
1 Lungs, kidneys or liver. Inflammation may cause pneumonia, bronchitis or other problems in your lungs; may lead to problems with kidney function; and may cause hepatitis or cirrhosis in your liver.  Lymph nodes. A small percentage of people with Sjogren's syndrome develop cancer of the lymph nodes (lymphoma).
Knowledge center. Sjogren's syndrome (Sjoegrens SjÃ¶grens) syndrome is a chronic disorder of the immune-system a-long term autoimmune-disease in which the'patient s white blood cells attack the saliva and tear, glands leading to dry mouth and eyes because the'body s tear and saliva production is. reduced