A hangover can occur in anyone after a single episode of heavy alcohol use. Symptoms include headache, nausea, vomiting, sweating, fatigue, shakiness, sensitivity to light and irritability.4

Typically, symptoms start a few hours after drinking stops, when blood alcohol is falling, and peak at the time the blood alcohol concentration is zero, but may continue for 24 hours after this. Alcohol causes hangover symptoms through dehydration (which causes thirst, dizziness and weakness), irritation of the stomach and liver (which causes nausea, vomiting and stomach pain), low blood sugar (which causes fatigue and mood changes), and disturbance of sleep.72

The type of alcohol drunk may increase the chance of getting a hangover. Alcoholic drinks include compounds called congeners that add to the taste, smell or colour of the drink. Alcohol with fewer congeners, such as gin and vodka, may cause fewer hangover effects than alcohol with more congeners, such as brandy, whisky and red wine.72

The only cure for a hangover is time, although drinking water or fruit juice and eating bland food such as toast or crackers may help with dehydration and low blood sugar. Paracetamol should be avoided as this can be toxic to the liver during a hangover. Aspirin and anti-inflammatory medicines should also be avoided if nausea or stomach pain is present, as these can aggravate acute gastritis caused by alcohol, but antacids can be useful.72

Go to the body effects section for more information on the short and long-term effects that drinking alcohol has on your body.