My Vet has put my cat on the pill Tapazole,but it makes my cat sick. Will the gel form not cause this?

Unfortunately that is a side effect of the drug Tapazole. I am unfamiliar with the gel form but I am assuming it contains the same medication just in a different form. And if that is the case it still may cause vomiting as well. If this continues to be a problem you may want to ask your veterinarian about other treatment possibilities to either minimize the vomiting or to treat hyperthyroidism. check out my answer to a similiar question I discuss what the other treatment options are. http://answers.yahoo.com/question/index;...I had the same problem with my cat, even when we tried starting him off on a very small dose and gradually increasing it.  We were never able to get him to his full dose because he actually had an allergic reaction to the meds (welts all over his body). I've opted to have his thyroid treated with the radioactive shot.