system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
A 65 years old patient of coronary artery disease was on Aspirin for 2 years. He now complains of black stools. Abdominal examination is normal. What is the most probable diagnosis?
assistant
The correct answer is  None