I started using sodium triborate (Flea Busters) years ago because my kitty Wally (RB) had terrible reactions to all flea meds. It's cheap, lasts at least a year and is non-toxic - just sprinkle it on all the carpets, kitty condos, fabric covered furniture, etc. You can buy the powder in bulk and apply it yourself or in some areas Flea Busters will come to your house and do the application for you. Never had any fleas since......