Plavix (clopidogrel) is a prescription medicine used to prevent blood clots in people with a number of blood vessel conditions, as well as those recovering from a stroke or a heart attack. Plavix prevents blood from clotting and can therefore cause bleeding that won’t stop, including bleeding in your intestines or stomach. Such symptoms as coughing up blood, vomit that looks like coffee grounds, and black or bloody stools need to be reported to your health care provider as soon as possible to make sure you are helped on time. The following mild side effects can be sometimes experienced: dizziness, mild headache, cough, stomach pain, runny or stuffy nose, and sore throat. You will need to tell your health care provider about these side effects only if they get particularly severe, which is unlikely. Such health conditions as a stomach ulcer, ulcerative colitis, bleeding or blood clotting disorder, a history of stroke, liver disease, and kidney disease may affect the dose of Plavix you are prescribed, so make sure your doctor is aware of them. Take this drug as recommended with a full glass of water to provide for maximum efficiency. Try to avoid missing does, as it can affect the success of your treatment.