Doctors say bleeding ulcers like the one suffered by film director Peter Jackson are no longer common.
Sir Peter was admitted to Wellington hospital on Wednesday night with acute stomach pain and had emergency surgery for a perforated ulcer.
His production company says the illness is not expected to affect his commitment to direct The Hobbit, beyond a slight delay to filming.
Gastroenterologist John Wyeth says ulcers can be caused by the common gut bacteria infection Helicobacter pylori, or by anti-inflammatory drugs such as aspirin.
He told Morning Report that most ulcers are treated successfully with antibiotics before they require surgery, but some patients don't show any symptoms until complications occur.