If you have head lice, your doctor may prescribe a medication called Natroba. This product comes in the form of a liquid that is applied to the hair and scalp for ten minutes for one or two treatments. It may take less than one bottle or up to a full bottle per application. The most common side effect is skin irritation at the application site.

What Is Natroba?

Natroba® (spinosad) is a prescription medication approved for treating head lice. It can be used to treat children as young as four years of age.
(Click Natroba Uses for more information on this topic, including possible off-label uses.)

Who Makes Natroba?

Natroba is made by ParaPRO LLC.

How Does It Work?

The active ingredient (spinosad) causes lice to become hyperactive, after which they become paralyzed and die. Spinosad is derived from the fermentation of a certain type of soil bacteria. It is also used as an insecticide in lawn and garden products.

How Effective Is Natroba?

Two different clinical studies have compared Natroba to permethrin cream (Nix®) for treating head lice. In both studies, Natroba was much more effective. In one study, 84.6 percent of people given Natroba were free of lice 14 days after treatment, compared to only 44.9 percent of those given Nix. The other study showed similar results.

When and How to Use This Medicine

Some general considerations to keep in mind during treatment with Natroba include the following:
  • Natroba is usually applied one or two times, with seven days in between applications. The second application is needed only if live lice are still seen a week after the first treatment.
  • Be sure to shake the bottle well.
  • Apply the liquid to dry hair. Apply it to the scalp first, then apply it to the hair. Use enough (up to one full bottle, if necessary) to completely cover the hair and scalp.
  • Leave the liquid on for 10 minutes, then rinse thoroughly with warm water. You may shampoo the hair immediately after treatment.
  • Avoid contact with the eyes and face. This is best done by covering the face with a towel throughout the entire process.
  • You may use a lice comb to remove the dead lice, although this is not necessary.
  • For the medication to work properly, it must be used as prescribed. Natroba will not work if you do not use enough.
Written by/reviewed by: Kristi Monson, PharmD; Arthur Schoenstadt, MD
Last reviewed by: Kristi Monson, PharmD;
Last updated/reviewed:
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