Pesticide treatments

The pesticide treatments available, malathion and permethrin, work by poisoning the lice. There is evidence that levels of resistance to these treatments are rising .


  • Products containing malathion have been used for a number of years and it has a favourable safety record
  • However, there is evidence that levels of resistance to this agent are high
  • One recent UK study found that malathion eradicated lice in only 33% of those treated with it


  • Past evidence demonstrates eradication rates of between 19% and 67%
  • However, there is evidence that levels of resistance to this agent are high
  • The preparation currently available is not recommended by the British National Formulary for the treatment of head lice

Non pesticide treatments

Non-pesticide lotions work in a different way from conventional pesticide treatments. By coating the outside of the lice, they disrupt their ability to manage water causing them to die. This physical mode of action means there is theoretically no chance for the lice to build up a resistance. There are two main active ingredient options currently in use, dimeticone and isopropyl myristate. Based on clinical evidence, dimeticone is considered the most effective treatment of this nature and, in a recent study, was shown to be significantly more effective at eradicating lice than the pesticide alternative, malathion.


  • The current evidence suggests that dimeticone is an effective agent, with lice eradication rates of 97% in a recent study
  • Dimeticone provides a promising treatment option as its mode of action is one that is likely to avoid resistance issues
  • An overview published in the Drug and Therapeutics Bulletin concluded that on current evidence dimeticone should be seen as a useful alternative to products containing conventional pesticides


  • Clinical trials demonstrate 5% octanediol's efficacy killing both lice and eggs and that it is significantly superior to malathion over two treatments
  • The surface-active chemical has the potential to disrupt insect cuticular lipids, 'stripping away' the louse's outer lipid layer, causing death by dehydration
  • As it can be delivered in a water-based solution, it offers an attractive therapeutic alternative to other head lice treatments, in an easy to apply format
  • At 1% concentration, the compound can be used to help protect against infection.

"Based on the evidence currently available, I would recommend dimeticone as the first choice treatment option for head lice."
Ian Burgess, Director of the Medical Entomology Centre and advisor to the authors of the Stafford Report

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