Hi I did an endoscopy 12 months ago . a small bleeding ulcer was found. no H Pylori. I was on omeprazole for about 4 eeks and recovered . some months back the same symptoms of abdominal pains came again and I was again on omperazole 20mg twice a day for 3 weeks. now i am taking 20mg once every morning. past 2 days I also had a tablet or two of antacids during the day. last two days my stools were yellow on the outside and black inside. black stools rolled over by yellow stools. I have gas at times but since the onset of omerazole, no abdominal pains.,