If you're looking for a natural way to repel insects, oil of lemon eucalyptus is one answer. Its active ingredient is p-menthane-3,8-diol (PMD). This EPA-approved repellent provides the longest-lasting protection of all plant-based products [source: CDC]. It provides protection similar to products that contain low levels of DEET (a chemical we'll discuss on the next page). Oil of lemon eucalyptus poses no threats to the environment, and the only potential risk to your health is eye irritation if you apply the product directly to your face. It's effective in repelling mosquitoes, biting insects and gnats.
Other natural oils effective in repelling insects include citronella, cinnamon, castor, rosemary, lemongrass, cedar, clove, geranium and peppermint oils.