Here are some studies: Inhibition of acetylcholinesterase by Tea Tree oil. Essential oils in the management of the donkey louse....Conclusion: These results demonstrate that the inclusion of essential oil suspensions during grooming can be used to manage louse populations successfully. INTRODUCTION:  Pediculosis capitis is a public health problem with a high prevalence. The emergence of parasite resistance to conventional pediculicide is of great concern worldwide. RESULTS: The results showed 100% effectiveness; short time of death, ovicidal action, activity on the adhesion of the egg, and low toxicity.  The potential application of plant essential oils to control Pediculus humanus capitis (Anoplura: Pediculidae).  Activity of tea tree oil.....on head lice   Toxicity of essential and non-essential oils against the chewing louse, Bovicola (Werneckiella) ocellatus The potential effectiveness of essential oils as a treatment for headlice, Pediculus humanus capitis.