The chemical makeup of Spice can cause every side-effect (both good and bad) of mj and then some, up to and including heart attack, seizures, kidney failure and quite a few other things.. all depends on the mix of the spice.. and from what I've read in some googling in the past, there's really no strict QC for most of the Spice-type manufacturers, so you could have what may consider to be 'weak', then extremely potent.. in 2 different packs, bought at the same time. "Tainted" Spice is most commonly known for the Wyoming and Oregon kidney failure incidents, which included heavy amounts of back pain, stomach pain, vomiting.. from normal to bright red blood.
Without me rambling further, since it has a full-on CB1 agonist.. Spice, hypothetically/in theory based on prior medical tests on CB receptors.. should really inhibit the vomiting, as the partial CB1 does to help control vomiting in cancer patients after chemo.. this should do so, in a more intense/better/faster way. (This in no way is my way of saying 'Smoke spice to control vomiting'.. that could not be further from the truth.) That said, many of the other chemicals that are in Spice could really out-weigh the anti-vomit effect that should be present w/full CB1 agonist-type response, and it wouldn't surprise me if any of the other chemicals could have been what caused the throwing up blood. Out of curiosity, was the blood a bright red, or more black.. like coffee ground-type emesis?