Neem oil is a type of horticultural oil that comes from the seeds of the neem tree (Azadirachta indica). Horticultural oils are natural oils that are used to control pests, mites, and some diseases on plants. Neem oil contains azadirachtin, a compound that has insecticidal, antifungal, antiseptic and antihistamine properties, which makes it more effective than other horticultural oils in killing and repelling insects. Neem oil can be used as an all-season oil, meaning it can be applied both when plants are dormant and when they are in leaf. However, neem oil should be used with caution, as it can cause phytotoxicity (plant injury) if applied at high concentrations, under high temperatures, or on sensitive plants. Neem oil is also nonselective, meaning it can harm beneficial insects as well as pests. Therefore, neem oil should be used only when needed and according to the label instructions. Neem oil also contains other fatty acids and essential oils that have beneficial effects on the skin and hair. Neem oil can be used to treat skin conditions such as acne, eczema, psoriasis, scabies, ringworm and lice. Neem oil can also be used to moisturize, nourish and protect the skin from environmental damage.