Hi ! Good evening. I am Dr Shareef answering your query. If I were your doctor, after an initial clinical examination, I would advise you for a stool test for occult blood as black tarry stool could be due to any kind of repeated blood loss from your upper GI tract, specially with a history of ingestion of prednisone and any anti inflammatory drug. I would advise you to stop specially these two drugs which might be causing gastritis/ duodenal ulcer which might have bled and the blood turning black due to chemical degradation with gastric acid. I would also advise you not to consume any alcoholic beverages or to smoke if you do, and go for a proton pump inhibitor and an antacid liquid till you get yourself assessed possibly by an endoscopic examination by a gastro enterologist to rule out the bleeding either from a gastrif/duodenal ulcer, or from an esophageal varices due to your liver disease. I hope this information would help you in discussing with your family physician/treating doctor in further management of your problem. Please do not hesitate to ask in case of any further doubts. Thanks for choosing health care magic to clear doubts on your health problems. I wish you an early recovery. Dr Shareef.