Hello,
Steroids can irritate the lining of the stomach and may cause, or aggravate, a stomach ulcer. They do not cause ulcers or fistulas.
It was once commonly thought that stress, smoking, medications and diet were the principal causes of stomach ulcers. However, the Helicobacter pylori (H. pylori) bacterium is now known to be responsible for duodenal and stomach ulcers.
Gastro-gastric fistulas and ulcers are frequent and serious complications of gastric bypass surgery.
Gastro-gastric fistulas and ulcerations are likely the result of breakdown of the mucosa resulting from migrating staples and other foreign material used during the procedure.