Pyrethrum extract and piperonyl butoxide are pediculicides available in over-the-counter (OTC) medicines that kill head lice, body lice, pubic lice (crabs), and their eggs (nits). The two ingredients come together in medicines that kill lice and nits.

The combination of pyrethrum extract and piperonyl butoxide is approved by the U.S. Food and Drug Administration (FDA) and is safe and effective when used according to the Drug Facts label directions. It is very important to apply lice treatments containing pyrethrum extract and piperonyl butoxide to dry hair. Wetting the hair prior to use can dilute the treatment.

  • You are allergic to ragweed. Breathing difficulty or an asthmatic episode may occur.
  • You have difficulty breathing.
  • Eye irritation occurs.
  • Skin or scalp irritation continues or infection occurs.
  • You accidentally swallow the medicine. Immediately contact a healthcare provider or the poison control national helpline at 800.222.1222.
  • Talk to a healthcare provider before using a lice treatment containing pyrethrum extract and piperonyl butoxide on a child under the age of 2.
  • Click here for more information on giving OTCs to children.