If you find live head lice following a treatment, some resistance to the insecticide may be occurring. Lice should die within 10 to 30 minutes after treatment with pyrethrin or permethrin. If you find live lice after 30 minutes, suspect that resistance is occurring and discontinue use of that product. If you do not remove nits, the infestation will reoccur and the additional use of the treatment products will increase the treated person's exposure to these insecticides, as well as help select for resistance in the head louse population. If you want to avoid insecticides entirely, you could try using soap shampoos that contain coconut or olive oils.
Most soaps kill all stages of the louse except the egg.
Four shampoos about 3 days apart should kill most of the lice as each successive shampoo kills newly hatched eggs. Always combine shampooing with daily combing and a cleaning of the environment. Some people use coconut oil in the hair to serve as a repellent against lice in an effort to prevent infestation or reinfestation but there is no research data to indicate that this is effective. Hair Combing Combing the hair to remove nits and lice that survived the shampoo treatment is the key to successfully controlling this pest. This process is time consuming but critical for success.