It depends on what chemicals the person has swallowed. Some chemicals will do even more harm coming back up. Others need to be expelled as soon as possible. A poison control center (911) can tell you the appropriate thing to do in each situation.
Vomit
It depends on how much you swallow. If it is a large amount, you could get diarrhea and/or vomit.
When you swallow a lot of mud
Ipecac, my friend (it'll induce the body to vomit). Since gasoline will burn and eat your insides
maybe, if their vomit tastes like doggie treats. i don't think it will though.
100 Until you vomit them up
No. it is made out of chemicals and dye
It is not if u swallow just a little bit but if you swallow a pen full you could possibly vomit but it is not fatal.
You don't drink it. If you swallow instead of spit, you will probably vomit.
They might if they can get sick easily
Well, first eat somehting, anything like chicken, rice, meatballs, but dont eat candy. Chew it in your mouth but don't swallow it. Then drink some water but don't swallow it either. Then act as if you want to vomit and run to a toilet and spit out the things in your mouth. Everything should look like real vomit. However this is only useful if you don't want to go to school and want to fool your parents.
Drunk people should lay on their stomach so they do not swallow their tongue, and also so they don't choke on their vomit if they throw up.