Our kitten 2 months has been treated with this product because it had fleas. The product was effective for 48 hours because we find dead fleas on her cushion but after a week he was always so smart. We had to redo a treatment at 15 days interval (strongly advised) because the chips continued to lay eggs and we were quickly infested. Result, ineffective product and required to use fumigants to wash our kitten every 2 days to a maximum of walnut chips and use anti-parasite spray and powder ... Today our kitten 4 months and we finally managed to eliminate fleas from our kitten thanks to a Seresto necklace * which itself has proved very effective and almost the same price, I recommend this product for cats that already have chips but perhaps operation Does prevention.