-- Using an over-the-counter or prescription medicine, follow the instructions printed on the box or label. Hair that is longer than shoulder length may require two bottles. Be sure to note how long the medication should be left on the hair and how it should be washed out.
-- Do not use a combination shampoo/conditioner or conditioner alone before using the lice medicine. Refrain from washing the hair for a day or two after the lice medicine is removed.