Repels mosquitoes for up to 6 hours. DEET-free. Repels mosquitoes that may carry West Nile virus. The active ingredient in Repel Plant-Based Lemon Eucalyptus Insect Repellent is derived from the leaves of the lemon eucalyptus tree. It is designed to repel mosquitoes for up to 6 hours. Powered by Citriodiol: Nature's repellent. Questions or comments? Call 1-888-880-1181 or visit our website at www.repel.com.