If you know you have an ulcer dont wait. Get it treated asap!!!
Heres my story...
One night about 2 years ago I was sitting at my computer surfing the web and feeling like a million bucks. It was about 10:00 pm. Suddenly, I started getting a really bad headache that came on quickly as well as just general feeling of "bleh". I ignored it at first thinking "crap, I better not be getting sick." After about 10 mins it was getting worse so I decided to log off and went to lie down.
After laying in bed for a few minutes I knew something wasn't right. My stomach felt like it was the size of a basketball but at the same time felt empty and I was starting to sweat profusely. I got up and nearly blacked out. I made my way into the bathroom and well, to spare you the details, what came out can only be described as a cross between motor oil and blood.
I stood up to clean myself and fell to my knees nearly blacking out. I got back up and thats when I noticed I could hardly breathe. No matter how deep a breathe I tried to take, it was like there was no oxygen in the room. The next thing I remember, I woke up and was laying on the bathroom floor and had thrown up all over the place the same "motor oil and blood" combination. I managed to drag myself to the phone and called 911.
In the span of about 1 hour I went from feeling fine, to being strapped to a gurney in the back of an ambulance on the way to the hospital.
The cause? It turned out that I had an ulcer in my small intestine known as a duodenum ulcer that I knew nothing about. The ulcer in turn was caused by, as docrx pointed out, a bacteria known as Helicobacter Pylori, or H.Pylori.
I'm fine now, but looking back I had warning signs that I never took as signs of an ulcer. They were...
1. Constant burping. I could almost burp on command.
2. A feeling of constant "fullness"
3. Heartburn that would go away whenever I ate something/anything
Ulcers are NOT caused by smoking, stress, or eating spicy foods. Those can aggravate an ulcer and since most people (like me) dont know they have one until they do one of the above, people had always assumed those things caused ulcers. Stomach Acid does NOT cause ulcers either. The two causes known now are the above H.Pylori and certain prescribed medications.
Also, left untreated an ulcer can become cancerous so dont wait, if you can get it treated!!!
Sorry for the long post.