I think it’s because usually vomiting is associated with illness, and to keep yourself alive, it’s better to avoid illness. My guess is that’s the same reason we have (generally) an aversion to decay too, both smell and appearance, and also an aversion to excrement and other such things. All of these are things that can make you sick if you come into contact with while unprotected.
In addition to the other answers correctly pointing out vomiting is bad for you, we have an aversion to other people vomiting too – other people can set you off, or even just being in the same place as vomit.
Why? Think back to scavenging. The troop of proto-humans is all going to eat much the same food, because that’s what’s available. What happens if it is off or poisonous? You don’t want half the troop dying so as soon as one member vomits, that triggers the others and the possibly-offending meal is purged, the troop lives on.
Because it’s better avoided, it’s a last resort and can cause further complications especially if there’s a lot of stomach acid. It takes a surprising amount of strength and energy and can go wrong when you are very weak. Sick, weak people can choke on the vomit and die if they’re not in the right position when they throw up. The acid can burn the inside of your mouth and teeth and even if you accidentally get only a little bit down your windpipe, it burns like hell and can cause permanent scarring. Repeated vomiting can even damage your teeth. It really is an emergency procedure and your body only does it when it has no other options.
Latest Answers