There's no question that DEET is the most powerful, but it also has a certain toxicity, especially for kids. There are two substances, "Picaridin" and the oil of lemon eucalyptus that have been the only other things endorsed by the Centers for Disease Control and Prevention (CDC) and The World Health Organization as effective and non-toxic, natural alternatives to DEET. This is a great news in disease prevention. Even "Cutter," one of the biggest of DEET users, was one of the first to create a product using Picaridin. Now, Avon and other companies sell repellents using this nontoxic alternative. Picaridin is probably more effective and is better tested than the eucalyptus oil, but they are both worth considering.

Furthermore, they work on things made of plastics, synthetics, and sealants (clothing, camping gear, etc.) without damaging the material. DEET will damage many synthetic materials, and really works best when applied directly to the skin.