Depends on the brand you use. Several years ago when drops were first coming out I used HARTZ, yeh not a good idea, almost killed my cat. A few weeks later 20/20 did a special that this poduct has a toxin in it, what kind a toxin to cats. I saved the box and after the story came out I read the warning, the main thing was that I should not use it on fish, if they are worried about fish with fleas I should have known there was something up. Since then the only thing I use are products sold through an animal hospital, revolution or frontline. Please be careful on your choice.
It is better to have loved and lost, than never to have loved at all.
Advantage is probably the best. It kills the flea on contact, your pet doesnt have to be bitten by the flea to be killed. It is quite safe. Revolution is good to, but the flea has to bite to be killed. Stay away from pet store items. I work in a vet office and have seen cats come in in seizures from it.
Thanks for the replies. I have been buying it from the vet and following their recommendations. My cat is undergoing tests at the moment to find out if this is what he is allergic to. Hopefully have the result next week.
one of the best products to use is frontline plus. it kills fleas, flea eggs and ticks. it is recommended to put on once a month on cats. it is rare to have a reaction to it. it stays on the skin and is moved over the body by the oils in their skin. advantage is also good if you only want to kill the adult fleas. hartz is not a good product. it is a permethrin which has to soak into your cats blood stream. a lot of animals have reactions to this product. if you have dogs to do not use advantix on them. if a cat comes in contact with a dog at any time during the month and that dog has been treated with advantix it could send the cat into seizures.