Why Shampoos Don't Work

Over-the-counter shampoos containing peremthrin may kill live lice, but not always. Strains of peremthrin-resistant lice are becoming more and more common. Children under the age of two, people with asthma, allergies, seizures, pregnant and breastfeeding women should consult their physician before applying these shampoos.

These shampoos do not kill eggs under the age of four days, so manual removal is still the most important step in eradicating all lice.

The National Pediculosis Association believes that the mechanical removal is the safest and most effective way to remove nits and lice.