Having a cup or two of coffee in the morning is a ritual for many people to get a boost of energy and stimulate their bowels. But certain ingredients in coffee, particularly caffeine, can cause an upset stomach. Black tea also contains caffeine, as well as other constituents that can irritate your stomach, but its effects are often milder than coffee. It may require a trial-and-error approach to determine if black tea is less upsetting to your stomach than coffee, but if both cause you problems, it could be the sign of an underlying digestive problem. Consult a doctor for a proper diagnosis if this is the case.
The caffeine in coffee is the primary cause of an upset stomach, particularly if you drink a lot of it. The problem occurs because caffeine stimulates the production of stomach acid, which can irritate the stomach lining and cause an upset stomach in sensitive people. Coffee also contains two chemicals that when mixed with caffeine can contribute to stomach irritation, according to the American Chemical Society. The presence of these two chemicals means an upset stomach may still occur when drinking decaffeinated coffee, as it still contains some caffeine, albeit significantly less caffeine than regular coffee.
Black tea is made from the Camellia sinesis plant. Out of all the teas made from Camillia sinesis -- including green, white and oolong -- black tea is fermented the longest, so it has the most amount of caffeine. Although 1 cup of black tea, on average, contains less caffeine than coffee, digestive problems such as an upset stomach can still occur after drinking it. Black tea also contains tannins, which can increase acid production in the stomach, potentially contributing to an upset stomach in some individuals.
It may not make a difference what drink you choose, either black tea or coffee, if you have a digestive disorder. Drinking any beverage that contains caffeine or other chemicals that irritate the stomach -- such as the tannins found in tea -- may cause issues for those who have problems in their intestinal tract, as it can make their symptoms worse. For example, it's possible that a milder digestive disorder, such as irritable bowel syndrome, can go undetected, particularly in the initial stages, and that drinking either coffee or black tea is causing an upset stomach because it is merely making the problem worse.
Taking a trial-and-error approach might be necessary to determine if black tea is less irritating to your stomach than coffee, and trying different brands of teas, as well as decaffeinated coffees, might help. If both cause problems, switching to an herbal substitute, either chicory-based for coffee or any number of herbal teas, could be a solution. Most herbal drinks don't contain caffeine but may still offer stimulation to your system. If your stomach becomes really upset, or you experience other symptoms -- such as diarrhea, vomiting or cramping -- along with an upset stomach, avoid black tea and coffee completely until you can see a qualified health practitioner to rule out an intestinal disorder.