Ulcers do NOT cause diarrhea.
More Info: It is extremely rare for diarrhea to be a symptom of a peptic ulcer. In the uncommon case of ulcers caused by Zollinger-Ellison Syndrome (ZES) diarrhea may be a symptom.
Zollinger-Ellison Syndrome (ZES)
One of the least common causes of a peptic ulcer is called Zollinger-Ellison Syndrome or ZES. ZES is a syndrome where tumors called gastrinomas cause an excess of gastrin, which produces gastric acid, to be made by the body. The tumors that result from ZES are usually cancerous and require prompt treatment. In the case of ZES, which is an uncommon cause of ulcers, diarrhea may present itself before ulcer symptoms develop. People who use antacids to relieve ulcer symptoms may also experience diarrhea. Diarrhea can be a side effect of taking antacids, however, it is rarely a symptom of the ulcer itself. Antacids may make people suffering from ulcers feel better for a short period of time, however they are not able to heal peptic ulcers.
Common Ulcer Symptoms
The most common symptoms of peptic ulcers are commonly known as dyspepsia. These symptoms include pain or discomfort, bloating, a feeling of fullness and inability to drink as much liquid as usual, or a feeling of emptiness or hunger within an hour or two after eating. Other symptoms of dyspepsia include mild nausea, regurgitation, and burping. Emergency symptoms may include severe abdominal pain, severe nausea, and black or bloody bowel movements. Emergency symptoms necessitate an immediate emergency room visit.