Its active ingredients, fipronil and S-methoprene, work together to kill parasites and break the flea life cycle. Fipronil kills adult fleas and ticks, while S-methoprene prevents flea eggs ...

safe from flea infestation. That’s because fleas have a rapid and prolific life cycle. Adult cat fleas can live for four to 25 days and lay up to one egg per hour. The eggs then fall off your ...