What is catnip and how does it work
Discover how the chemical nepetalactone in catnip triggers euphoric behavior in two-thirds of cats, why the other third remain unaffected, and the specific biological mechanism behind this hereditary reaction.
About two-thirds of domestic cats react to catnip, while one-third are genetically immune, and the effect is triggered by a specific chemical called nepetalactone binding to receptors in the nose. This reaction is hereditary, temporary, and entirely harmless, though the underlying genetic mechanism is more complex than a simple on-off switch.
The chemical trigger is nepetalactone
The active ingredient in catnip is a terpene called nepetalactone, which is found in the plant's essential oil and is extracted via steam distillation. When a cat encounters the bruised leaves or stems, the nepetalactone binds to one or more olfactory receptors in the olfactory epithelium, not the vomeronasal organ. This binding mimics the scent of a feline pheromone, triggering a cascade of behavioral changes that range from rolling and rubbing to leaping and purring. The plant itself uses this chemical as a natural insect repellent, which is why it is effective against mosquitoes, flies, cockroaches, and termites.
Genetics determine the response
Not every cat has the same reaction, and this is not a matter of preference but of genetics. Approximately one-third of cats are genetically immune to the effects of nepetalactone and will show no behavioral change regardless of exposure. The ability to react is hereditary, but the inheritance pattern is not as simple as a single dominant gene. Early studies suggested a Mendelian-dominant trait, but a 2011 pedigree analysis of 210 cats indicated a polygenic liability threshold model with heritabilities between 0.51 and 0.89. This means multiple genes likely contribute to the sensitivity, making the response a matter of biological threshold rather than a simple binary trait.
Age and duration of the effect
Very young cats often do not react to catnip until they are older. Kittens younger than six months typically do not exhibit the characteristic behavioral changes, and the sensitivity usually develops as they mature. Once a cat is exposed, the main response period generally lasts between 5 and 15 minutes. After this window, olfactory fatigue sets in, and the cat becomes temporarily unresponsive to the scent. This is a natural reset mechanism; the cat does not need to wait days to react again, but immediate re-exposure yields no result until the receptors reset.
Behavioral symptoms and safety
The typical reaction involves a sequence of behaviors: rubbing against the plant, rolling on the ground, pawing at the leaves, and licking or chewing them. Ingestion often leads to drooling, sleepiness, anxiety, and increased vocalization, with some cats growling or biting at the hand holding the plant. While the behavior can appear manic, it is not dangerous. The plant is a short-lived perennial herb that is drought-tolerant and deer-resistant, and it poses no toxicity risk to cats. However, because the plant is an insect repellent, it is worth noting that the same chemical properties that affect cats also deter pests like aphids and squash bugs in a garden setting.
Other species and alternative plants
The reaction to nepetalactone is not limited to domestic cats. Large felines such as leopards, cougars, servals, and lynxes often react strongly in a similar manner. Lions and tigers may also react, though their responses are less consistent. For the one-third of domestic cats that are immune to catnip, there are alternative plants that can induce similar euphoric states. These include valerian root, silver vine (matatabi), and Tatarian honeysuckle wood, which contain different iridoids that trigger comparable behavioral responses in non-responsive cats.
Human uses and historical context
Catnip has a long history of use by humans, with the name derived from medieval Latin terms meaning "of cats." The plant was described by Carl Linnaeus in 1753 and has been used in herbal teas for its sedative and relaxant properties to treat stomach cramps, indigestion, and fevers. While modern medicine has largely replaced these traditional uses, the plant remains a popular ornamental garden plant. Its ability to repel insects makes it a useful companion plant, and specific cultivars like lemon catmint are grown for their distinct scent. Despite its long history and wide naturalization across Europe, Asia, and North America, its primary fame remains its unique and temporary effect on the feline sense of smell.