Hangovers get worse as we get older, and it’s one of many reasons people decide to quit or cut back on drinking. About 76% of people reported getting mild or moderate hangovers after moderate drinking in one test. It’s a familiar pain for anyone who occasionally drinks too much.

But the rumors fly about how to cure hangovers (see “Hungover: the Morning After and One Man’s Quest for the Cure" for an exploration of many ideas), and there are few clear pieces of guidance out there.

Here’s what we found after doing a little digging:

Hangovers are not caused by dehydration. This is one of the most common misconceptions about hangovers (one I believed, before I did the research). Dehydration is one aspect of why your head hurts, but it’s not the main reason. Drinking water will help in some cases, but isn’t a cure. In fact, one study found no correlation between hangovers and dehydration.
It doesn’t matter in what order you drink what type of alcohol. Scientists have helped us all out and actually studied this. Beer before wine is just as bad as wine before beer. It does, of course, matter how much alcohol you consume, relative to your own body size. The drunker you get, the worse your hangover will be.
Hangovers are partially caused by a toxic compound. When you process alcohol in your liver (and in other places), the enzyme alcohol dehydrogenase turns alcohol into acetaldehyde. Before it is broken down further into acetate, acetaldehyde lingering in the body leads to memory problems, sleepiness, lack of coordination, sweating, and nausea. Acetaldehyde is also a known carcinogen.
Hangovers are partly caused by inflammation. Hangovers appear to be correlated to high levels of cytokines, which your immune system uses to communicate when it’s battling inflammation. Anti-inflammatory medicines can also help with fighting the symptoms of a hangover.

Hangovers are a natural consequence of your body breaking down alcohol, and they get worse the more you consume. The only way to avoid them entirely is not to drink at all, or drink in moderation.