Why do i vomit so much when i'm drunk?

Alcohol is poison: Vomiting is a primitive reflex that developed so that the body could rid itself of a poison before it causes damage. There is little nutritional value to alcohol. On the contrary, too much alcohol will hurt you--both acutely & over a prolonged exposure (see prior healthtap answers regarding alcohol toxicity). Your body is only trying to protect itself--listen to it & cut back your consumption.