Throw up And Then Swallow

by Maria
(Canada)

My son is 3 years old and has had a bad cold for the pass 4 days. Just recently his cough as broke causing him to choke on his spit when he cough. i know its just a cold. since he has no fever and in general is still happy.

What i want to know is why does he throw up in his mouth and swallow it? we out him over the toilet when he is going though one of these spells. but he is so panicky he refuses too...any idea what could be causing this
thanks