The Peter Gurney Guinea Pig Health Guide
I have put heaving hiccups in because though it is nothing more than an defence mechanism guinea pigs have to clear air blocks, or something which, to use the proverbial term, 'Has gone down the wrong way,' it is very alarming to see the first time around.
The guinea pig will heave up as though it is about to vomit, only it is far more violent and traumatic than the same kind of thing seen in humans. The whole body rocks forward, and I have even seen a couple fall over sideways with the sheer force of it.
The reason it is so much more of a forceful spasm than that seen in the human kind is because it cannot vomit!. In essence anything that goes down it throat can only come out through the back end, the animal's digestive system is designed that way.
The guinea pig can have five or six of these spasms and they can get more violent as they progress, then suddenly there is a hiccup, a cough sometimes and that's it, all over, and it will go back to what it was doing before the heaving started.
By this time, of course, the owner is as likely to be about the throw a wobbly her or himself. I certainly did the first time I saw it. I can only suggest a good stiff Scotch as an excellent restorative, for the owner, that is!