CHERISTIN FLEA CONTROL FOR CATS! posted: Wed Aug 09 09:07:59 EDT 2017 by: cah Tags: "Clinic Specials" "News" We are now offering Cheristin monthly topical flea control for cats. Fast acting & effective. Starts working in 30 minutes, kills 100% of fleas in 12 hours in a controlled study. For cats and kittens 8 weeks and older.