There are many types of at-home cures for lice, but over-the-counter medicated lice shampoos should be used twice to effectively eliminate lice, according to WebMD. The medicated shampoos, called pediculicides, should be used again 10 days after the first application.
Nits can be resistant to over-the-counter shampoos and are able to hatch after the initial treatment, explains WebMD. The second treatment kills any nits that may have hatched before they are able to produce eggs. Most over-the-counter medicated shampoos for lice should be applied to dry hair for 10 minutes and then rinsed off. If lice are still present after two doses of treatment, medical treatment may be necessary.