The active ingredient, which causes unusual behavior in cats, is a volatile oil called nepetalactone, which can be found in the leaves & stem of the plant. It is also interesting to note that this essential oil was found in one study to be about ten times more effective at repelling mosquitoes than DEET, which is the active ingredient in most insect repellents. It has a long tradition in England and France as a kitchen aid. It was also used occasionally as a stimulating drink until the introduction of black tea. Several Native American tribes used it to support immune function and for relaxing muscle spasm and cramps associated with digestion. Catnip supports healthy digestive motility. The Mohegan tribes relieved infant colic with a tea made from the leaves.