Have you ever been fine, then stood up too fast? That’s your inner ear’s fault. Alcohol messes with your brain’s balance center, the cerebellum. It thinks you’re spinning even if you’re just walking to the fridge.
This disconnect between your eyes (seeing a still room) and your inner ear (sensing a tilt-a-whirl) causes motion sickness. Your brain assumes you’ve been poisoned and initiates a full system purge. It’s the same reason you get sick on a rollercoaster, except your ride is a barstool.
What Is It When You Throw Up In Your Mouth at Winnifred Pitts blog
Your body doesn't know the difference between a fun buzz and a deadly poison. To your nervous system, they look the same. It chooses to be safe rather than sorry.
You’re Dehydrated, Dummy
Alcohol is a diuretic, which is a fancy word for “makes you pee a lot.” You lose more water than you take in. That’s why you wake up with a mouth like a desert.
Dehydration is a huge trigger for vomiting. Your body is literally running dry, and your brain says, “Get rid of the liquid that’s making this worse.” It’s a cruel irony: you’re drinking to feel good, but you’re simultaneously drying out your insides. It’s like trying to put out a fire with gasoline.