I first became interested in feverfew as a treatment for an older cat of mine. Feverfew can be used as a pain reliever in cats, (or dogs) as an alternative to aspirin which are toxic to felines. You can use a glycerin-based tincture or a teaspoon dose cooled tea in drinking water. I could never get my cat to drink it, however, feverfew did work well for a flea rinse. Feverfew contain compounds known to paralyze fleas. Works best as a rinse made from fresh flowers.