When you drink alcohol, your body tries to metabolize the toxins in an efficient manner. But when the toxins get too much for your body to handle, you get a hangover.

Alcohol acts as a diuretic and causes your body to release more urine than normal. When you are drinking alcohol, your body needs more water than normal because your kidneys and live need the water to process the toxins. If you don’t have enough water and fluids available, your body redistributes whatever water is available. Every part of your body is affected by this, which is why you get hangover headaches. Your body will be dehydrated so you need to replenish.

Congeners are another cause of hangovers. They are impurities that are created during the fermentation process of some types of alcohols. Cheaper liquors generally have higher levels of congeners because they go through less of a filtration process. Dark liquors (whiskey, red wine, dark rum, etc.) are the same way, so try to stay away from these.

Find out how to prevent hangovers and how to cure hangovers.