Advantage Flea Side Effects Is Advantage For Cats Safe?

Is Advantage for cats safe? - advantage flea side effects

I have my cat Advantage (flea medication) just wanted to make sure that it is safe before putting them on my cat?
Do you ever do?
Are there any side effects that can have this?
Oh, and they used before, but it was started about 1 year only on the new chips. I also think that you are allergic to flea bites!