From the manufacturer

Natrapel Oil of Lemon Eucalyptus Tick Repellent naturally repels ticks for up to four hours. Oil of lemon eucalyptus is the only plant based active ingredient recommended by the CDC. It is a DEET free insect repellent that keeps ticks at bay without relying on chemicals. Made using lemon eucalyptus tree leaves, it has a refressing scent and a non-oily feel and repels ticks that may carry Lyme disease.