Hedrin lotion contains the active ingredient dimeticone which is a silicone based substance it is used to treat head lice infestations hedrin works in a different way to conventional insecticides for head lice instead of poisoning the parasites by chemical means the dimeticone in hedrin lotion works by physically coating and smothering the lice this prevents them from being able to excrete excess water and this kills the lice head lice cannot become resistant to the lotion because