Lufenuron and Nitenpyram Together in one capsule, KILL fleas Instantly and control them for 1 month. Lufenuron kills flea eggs and larvae for a month, Nitenpyran provides fast flea relief for your cat. In fact, it begins to work within 30 minutes to kill adult fleas and continues for 24 hours. In order to work Lufenuron has to be given on a regular basis, once a month and HAS to be given with a full fatty meal otherwise it will not work. NO SIDE EFFECTS OR TOXICITY have been reported even in animals fed hundreds of times the recommended dose that makes it extremely safe for cats and dogs.