Vomit is a liquid, produced when drinking or eating something in the environment that wasn't digestible. The player character will expel the substance after receiving the food poisoning or wasted debuff, and will regularly throw up vomit onto the ground, losing 10% satiation every time. Certain status effects (both positive and negative) such as poison will be removed when vomiting. The player will produce vomit even if there is no remaining satiation.
As vomit does not stain the player, it will remove any active stains if you completely submerge yourself in it.