The NHS names coffee as a food and drink that can cause or worsen heartburn.
Caffeine relaxes the valve between stomach and esophagus, and coffee stimulates acid production, so the acid has both motive and opportunity. Smaller, weaker cups with food, no coffee near bedtime, and staying upright after drinking it solve most cases; decaf helps some people but not all, since caffeine is only part of the problem. Pharmacy antacids cover occasional flares. Heartburn most days, trouble swallowing, vomiting, or weight loss is the GP version.
What to do
Common questions
Why do I get heartburn from coffee?
You are not imagining it: the NHS lists coffee among the food and drink that can cause or worsen heartburn, alongside tomatoes, alcohol, chocolate, and fatty or spicy foods. Coffee's trouble is twofold: caffeine relaxes the muscular valve between your stomach and esophagus, letting acid splash upward, and coffee itself stimulates stomach acid production. Whether decaf escapes the effect varies by person, since it removes the caffeine but not all of the acid-stimulating compounds. The fixes are worth trying in order: cut the dose (one cup, smaller, or weaker), drink it with food rather than on an empty stomach, avoid lying down or bending over right after, and skip coffee within 3 to 4 hours of bed, since the NHS advises not eating or drinking trigger foods close to bedtime. If you cannot give it up, try a darker roast or cold brew, which some people tolerate better, and keep an antacid from the pharmacy on hand for occasional flare-ups. See a pharmacist for heartburn that keeps coming back, and a GP if you have heartburn most days, difficulty swallowing, persistent vomiting, or unintended weight loss, because frequent reflux deserves treatment, not just antacids.