Hi & Welcome to HCM. I can understand your concern regarding the safety of Coumadin. Incomplete data: Age, gender, any other associated medical illness or medications intake?? Coumadin (Warfarin) is prescribed to prevent blood clots. If taken incorrectly, increases your risk of dangerous bleeding. It s side effects can also include interactions with some foods, prescription medicines and over-the-counter supplements. The most common side effects include: Bleeding, including heavier than normal menstrual bleeding, red or brown urine, black or bloody stool, joint pain, discomfort or swelling, especially after an injury, vomiting of blood or material that looks like coffee grounds, bruising that develops without an injury you remember, etc. It may interfere with the metabolism/clearance of other medications. Its metabolism/clearance may be affected by liver disease or certain medications. Hope this answers your query.