Hedrin Spray Hedrin Spray is used to eradicate headlice infestations & does not have the nasty smell that some other headlice treatments have. Headlice will not develop a resistance against Hedrin Spray, as it does not use pesticides. The spray works by covering the head louse & effectively drowning it. Hedrin Spray is suitable for everyone from 6 months old to adult. Ingredients Active substance: Dimeticone (4% w/w). Other ingredient: Cyclomethicone 5. Directions Adults & children over 6 months: Apply to dry hair. Ensure that no part of the scalp is left uncovered & that hair is covered evenly from root to tip with the spray. Hair should be left to dry naturally. Hedrin Spray must be left on the hair for a minimum of 8 hours or overnight. The spray should be washed out with normal shampoo & then rinsed thoroughly with water. The treatment should be repeated after seven days. Children under 6 months: Only to be treated under medical supervision.