According to the Centers for Disease Control and Prevention, the best treatment for head lice includes the use of over-the-counter medicines with the active ingredient of pyrethrins or a 1 percent solution of permethrin lotion. WebMD also recommends the use of shampoos containing piperonyl butoxide.
According to the CDC, the ideal process of treating lice should be an ongoing plan that spans at least nine days. After washing all of the infested person's clothing, apply the treatment as directed and instruct the infested person to put on a set of clean clothes. If after eight-to-12 hours, no live lice are found or the lice are slow-moving, the medicine is working and another treatment is not necessary.
If the lice are still as active as before or no dead lice are found, the CDC recommends speaking to a health care provider. For the next few days after treatment, use a nit comb to remove additional lice and nits to decrease the risk of self reinfestation. Most over-the-counter treatments include instructions to treat again after seven or nine days. This is because most treatments do not kill lice eggs and the second treatment ensures newly hatched lice are killed before they are allowed to lay additional eggs.