Any of those over the counter, store bought flea stuff is bad for your cat…!!! My cat almost died of that junk…almost 5 yrs ago…also make sure that when you use flea medication you dont use anything else for 30 days or this will be considered an overdose. Also flea collars are just as bad. Words straight from my vet‘s mouth is those drops and collars that you purchase from the store are POISON!!!