Clinically proven to kill head lice and eggs in one 15 minute treatment easy to apply skin friendly no nasty odour contains no pesticides with penetrol to boost egg kill hedrin once spray gel eliminates head lice and their eggs in adults and children aged 6 months and overit works by physically smothering the lice and also contains penetrol which helps the product to penetrate louse eggs in order to kill them the gel can safely be used as often as required without lice developing resista