Although catnip has a stimulating effect on virtually all felines, in humans it is traditionally used as a sleep aid. It has also been used for digestive and menstrual problems, as a uterine stimulant in childbirth, and as a symptomatic treatment for colds. Publications from the late 1960s suggested that the plant, when smoked, produced a psychedelic high not unlike marijuana, but it was later discovered that the researchers had, in fact, mixed up the two plants.1,2

Catnip is primarily used by today's herbalists as a treatment for insomnia, as well as for mild stomach upset, especially when caused by stress. One ingredient of catnip, trans-cis-nepetalactone, is the active ingredient so far as cats are concerned. Most (but not all) cats respond to this substance with a complex reaction called the "catnip response" that can go on for about an hour.

Nepetalactone is similar to a class of substances called valepotriates, found in the sedative herb valerian.3 This has attracted some attention, as valerian also is used for insomnia and stomach discomfort. However, as valepotriates are no longer considered to be the active ingredients in valerian, it is not clear that this relationship has any significance.

As yet, there is no real evidence that catnip produces any effect at all in humans. Tests conducted on chicks and rats have produced conflicting results, although high doses of essential oilof catnip have increased sleeping times in the latter.4,5