garlic cloves
I've never actually tried to feed either of my dogs actual cloves, but someone once told me to put a dash of garlic powder across their food. Never even has to be enough they notice it, just enough to get in thru their bloodstream, it exudes a bitter taste in their skin.
Charlie is the first pup I've ever seen puff up like a puffalump from a reaction to anything. Fireants and spiders it seems sends his skin into fits, it starts off a bump, then a lump, and then he just looks like a stitched up puffalump dog. Gawd love Benedryl because the first time that happened to him, I didnt think to actually give him a tablet and I had to search frantically for vets as mine.......couldnt take him at the moment. Dont you know I got a new vet that night. But sure enough it happened again and one lil baby tablet of Benedryl and he didnt make it to puffy again. But anyhow long story short if he wont take a clove, try a sprinkle of powder in the food.