Stomach ulcers, also referred to as gastric ulcers, are lesions formed in the lining of the stomach. It was previously thought that stress and a poor diet caused ulcers, but that was found to be untrue. In most cases, ulcers are caused by a bacteria, but certain medications can also cause ulcers. While coffee does not cause stomach ulcers, it can potentially irritate an existing one. Avoiding coffee and other caffeinated products is often recommended for those suffering from a stomach ulcer.
The acid in the stomach is very strong and helps break down certain foods for digestion. The acid is strong enough to cause damage to the cell walls of the stomach, but they are protected by an inner lining that neutralizes the acid. If that lining is damaged, the acid present can easily cause damage, which results in an ulcer. The most common cause of a stomach ulcer is the bacteria Helicobacter pylori, which weakens the stomach wall. Taking medications that damage the stomach lining -- such as aspirin, ibuprofen or naproxen -- are another common cause of ulcers.
Coffee has many constituents, but the most well-known is caffeine, which is also known to increase production of stomach acid. In addition, coffee contains other components that increase acid production. In 2010, researchers at the American Chemical Society identified two such substances: catechols and N-alkanoly-5-hydroxytryptamides. Both substances stimulate the mechanisms of stomach acid secretion in human stomach cells. The researchers reported that it was a mixture of the constituents that caused increased acid production, not just one of them alone.
Coffee does not produce enough of an effect to actually cause an ulcer, but the components in coffee that increase acid production in the stomach can irritate an already formed ulcer. In addition to potentially causing pain, coffee may slow down the healing process and make you more susceptible to damage by the original cause of the ulcer, according to the University of Maryland Medical Center. As caffeine is not the only component of coffee that increases stomach acid, drinking decaffeinated coffee can also be potentially harmful to a stomach ulcer.
Not everyone with an ulcer will have problems drinking coffee, but avoiding coffee of any kind, including decaffeinated coffee, as well as other drinks that contain caffeine, is recommended. In some cases, a coffee alternative -- such as chicory root -- that doesn't have caffeine or other acid-producing constituents may help ease cravings for coffee without the negative effects. Some herbal teas, such as licorice, can also act as a substitute and may help reduce any damage caused by an ulcer. Consult your doctor before drinking any kind of coffee substitute.