Has anyone else taken coumadin and had to deal with an ulcer? This past March during all of the testing to find out about the state of my pulmonary valve it was discovered that I have a bleeding gastric ulcer. I did not have it before I had surgery the first time so, I was just wondering if ths was a side effect of coumadin and if taking coumadin could increase the chances of bleeding if you have an ulcer when you begin taking coumadin. I have looked at every coumadin reference I could find and cannnot find any specific info on coumadin and gastric ulcers. Anyone who has found something like this please let me know.