Jasper is allergic to most chemical flea treatments. He seems ok with the johnsons flea tablets but they are a cure not a prevention. Does any one have any suggestions for natural alternatives to discourage fleas? My vet told me garlic and tea tree but someone on here has told me tea tree is toxic to cats!! I need some kind of preventative measure as Jasper is an avid mouser and often brings back the most disgusting parasite ridden things.