Catnip is a member of the mint family,
but it is better known for making cats go into a euphoric frenzy,
rubbing on everything and rolling on the ground. Only about half of
cats react to catnip for some genetic reason that no one
understands.
Many insects are also sensitive to the oil in catnip, however they
hate it. Lab tests from one study show that catnip is ten times more
effective at repelling mosquitoes than DEET, and another study found
that it has the same ill effect on bloodsucking flies that attack
livestock.
Follow-up studies showed that the oil in catnip was not quite as
effective as DEET when used directly on skin. Many people use catnip
oil as insect repellent, because it is nontoxic and 100 percent
natural.
No one understands why catnip makes such a good insect repellent.
Maybe the bugs cannot stand the smell, or maybe catnip acts as an
irritant to them.