Bio Spot Spot On for Cats is especially formulated for cats to provide 30-day protection to kill fleas, flea eggs and deer ticks. Also kills and repels mosquitoes that may transmit heartworm disease. Contains Etofenprox and methoprene (same IGR has Frontline) to prevent reinfestation and to break the flea life cycle. Do not use on kittens less than 12 weeks of age. Do not reapply more often than every 30 days. Do not get in catís eyes or mouth.