Put simply, alcohol irritates your digestive system. Drinking – even a little – makes your stomach produce more acid than usual, which can in turn cause gastritis (the inflammation of the stomach lining). This triggers stomach pain, vomiting, diarrhoea and, in heavy drinkers, even bleeding.
“In the longer term, alcohol is associated with an increased risk of cancer of the mouth, tongue, lip, throat, stomach, pancreas and colon,” says Dr Moriarty. “Other digestive problems caused by drinking too much include acid reflux – where stomach acid burns your throat. Alcohol can also contribute to developing a peptic ulcer – a painful, open sore in your stomach lining.”
Dr Moriarty points out that vomiting, especially if you’re very drunk and not in control, carries its own risks.
“If you’re close to unconsciousness and are sick, you can breathe vomit into your lungs, and not be able to cough it back up. This can lead to death,” he says. “Violent vomiting can tear your throat too, meaning you can vomit blood. Usually, this settles on its own, but occasionally bleeding can be severe and life-threatening.”
Drinking can also make it more difficult to digest food and absorb vital nutrients, particularly proteins and vitamins.1 That’s because alcohol reduces the amount of digestive enzymes which the pancreas produces to help us to break down the fats and carbohydrates we eat.1
People with Irritable Bowel Syndrome (IBS) may find their symptoms get worse if they drink alcohol. Drinking to excess can cause symptoms that mirror IBS (stomach pain or diarrohoea).2
You may have heard suggestions for how you can avoid a stomach upset and ease the ill-effects of alcohol on your stomach. These include not mixing drinks, eating, drinking plenty of water and not mixing painkillers with alcohol. But do any of them actually work?
Mixing drinks: Does mixing drinks really have an effect on how drunk you get? Mixing drinks makes it more difficult for you to keep track of what you’re consuming, so it’s likely you’ll drink more alcohol than you would just sticking to one type of drink. The more you drink, the more likely you are to be physically sick and feel hungover afterwards. “There’s little evidence that it would make the effects on your stomach any worse though,” says Dr Moriarty.
Painkillers: While they’ll make a pounding head feel better, painkillers can have the opposite effect on your stomach. “Painkillers, such as aspirin, can further damage the lining of the gut,” says Dr Moriarty. “Paracetamol is an effective pain killer. But rather than taking pills to settle an upset stomach after drinking, try an antacid, or a cup of mint tea instead.”
Food facts: Eating something, preferably carbohydrate-rich food, before you start drinking may help slow the rate your body absorbs the alcohol. Drinking water or soft drinks throughout the night will also slow your drinking down. Both can help you drink less overall, lessening the ill effects on your stomach.
(1) Lieber, C. S. (2003). Relationships between nutrition, alcohol use, and liver disease. Alcohol Research and Health, 27, 220-231. Accessed 24 February 2016. Available at:
(2) NHS Choices website. Irritable bowel syndrome (IBS) – Causes. The Information Standard member organisation. Last reviewed: 25/09/2014. Available at: