The dangers posed by extracts from naturally occurring plants would seem to pale into insignificance compared to the health hazards associated with modern insecticides. Especially when they’re applied to the scalp, which is known to be far more absorbent than other areas of the body.

Children in particular have less well-developed immune and detox systems, and a number of studies indicate they have a higher sensitivity to pesticide toxins.

The UK support group, The Pesticide Exposure Group of Sufferers (PEGS), has received a number of reports of allergic reactions to chemical-based head lice treatments. Symptoms range from burning sensations to acute hallucinations, and include headaches, dizziness, hyperactivity, and a general lack of energy.

The Department of Health’s ‘Medicine Control Agency’ currently licenses four main pesticide active ingredients for use in head lice lotions: malathion, carbaryl, and the synthetic pyrethroids; permetherin and phenorthrin.

But an increasing number of reports suggest these chemicals may have dangerous side-effects. Particularly when combined (often unknowingly) with other chemical toxins.