Neem oil has been shown to be effective against all stages of head lice, and the Neem left behind in hair can help prevent a reinfestation. Neem extracts interfere with the parasites ability to feed and hatch eggs. Apply a Neem shampoo or pure Neem oil, let stand at least 10 minutes before rinsing. Continue to wash daily with Neem soap, Neem shampoo, or pure Neem oil. Wash Contaminated clothing and bedding with a Neem soap in very hot water.