Hedrin once spray gel is a liquid gel for the eradication of head lice and eggs it works by physically smothering the lice it 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 the lice developing resistancedirections1 cover the shoulders with a towel2 shake the bottle well before each use3 holding the spray approximately 10cm from the hair carefully spray sufficient amounts of gel evenly over d