Roaches don't go crazy over catnip.

A feline friend may go into ecstasy over a whiff of catnip, but the same odor will send a cockroach skittering away, according to entomologists at Iowa State University in Ames. Their finding may lead to new roach repellents based on an active compound found in the catnip herb, Nepeta cataria.

Chris J. Peterson and Joel R. Coats tested the reaction of German cockroaches to two forms of nepetalactone, the herbal compound that drives cats wild. The researchers gave insects a choice of walking on either a piece of paper treated with nepetalactone or untreated paper. For driving away roaches, one form of the compound was 100 times as effective as deet, an ingredient found in commercial insect repellents. Removing roaches' antennas rendered them indifferent to nepetalactone, revealing that receptors on those structures, rather than on their feet or mouthparts, respond to the compound.

The researchers are now testing nepetalactone's effect on mosquitoes. An insect repellent based on catnip could be safe to use on people and have a more pleasant smell than the ones currently on the market do. The only obvious drawback, they note, is that although such a product would keep insects at bay, it might draw unwanted attention from cats.