There's no genuine "cure" for a hangover — the only sure way to avoid one is to drink less, drink slowly, and alternate alcoholic drinks with water. Once a hangover has set in, the symptoms are mostly down to dehydration, low blood sugar and disrupted sleep, so the most effective remedies simply address those directly.
Rehydrating with water, eating something plain and easy to digest, getting rest, and giving your body time are the closest things to a genuine remedy. Painkillers can help with headaches, but check the packet if you've also taken paracetamol, and avoid more alcohol as a "cure" — it only delays the symptoms.
Common questions
Is there a genuine cure for a hangover?
No, the only sure way to avoid one is to drink less, drink slowly, and alternate alcoholic drinks with water.
What actually helps once a hangover has set in?
Rehydrating with water, eating something plain and easy to digest, getting rest, and giving your body time.