Malathion treats head lice. Apply this medication to dry hair and scalp only. Do not apply to wet hair.

Malathion Overview

Reviewed: August 15, 2013

Malathion is a prescription medication used to treat head lice (tiny insects that live on humans, usually found in hair). Malathion belongs to a group of drugs called pediculicides. It works by killing lice.

This medication comes as a lotion to be applied to the scalp and hair and is left on for 8 to 12 hours. If adult lice are found 7 to 9 days after treatment, a second application may be required.

Common side effects include skin or scalp irritation and stinging.

Warning: Malathion Lotion is flammable. Do not expose lotion and wet hair to open flames. Do not smoke while applying malathion lotion or while hair is wet.

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Malathion Cautionary Labels


Uses of Malathion

Malathion is a prescription medication used to treat head lice (Pediculus humanus capitis) in adults and children 6 years of age and older.

This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.

Malathion Brand Names

Malathion may be found in some form under the following brand names:

Malathion Drug Class

Malathion is part of the drug class:

Side Effects of Malathion

Common side effects of malathion include:

  • skin and scalp irritation
  • stinging
  • chemical burns 

This is not a complete list of malathion side effects. Ask your doctor or pharmacist for more information.

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Malathion Interactions

Malathion is unlikely to affect the actions of other medications you are taking, and other medications are unlikely to affect malathion.

No malathion drug interactions have been identified, however, you should tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements. Not all drug interactions are known or reported and new drug interactions are continually being reported.

Malathion Precautions

  • Warning: Malation is flammable. The lotion and wet hair should not be exposed to open flames or electric heat sources, including hair dryers and electric curlers. Do not smoke while applying lotion or while hair is wet.
  • Allow hair to dry naturally and to remain uncovered after application of malation Lotion.
  • Malation should only be used on children under the direct supervision of an adult.
  • If malation lotion comes into contact with the eyes, flush immediately with water. Consult a physician if eye irritation persists.
  • If skin irritation occurs, discontinue use of product until irritation clears. Reapply the malation lotion, and if irritation reoccurs, consult a physician.
  • Chemical burns including second-degree burns and stinging sensations may occur with the use of malation lotion.

Important: For use on scalp hair and scalp only. Do not get malation lotion in your eyes, mouth, or vagina.

Do not use malation if you are allergic to any of its ingredients.

Malation should not be used in infants and children younger than 2 years of age.

Malathion Food Interactions

Medicines can interact with certain foods. In some cases, this may be harmful and your doctor may advise you to avoid certain foods. In the case of malathion there are no specific foods that you must exclude from your diet when receiving this medication.

Inform MD

Before receiving this medication, tell your doctor about all of your medical conditions including if you:

  • are allergic to any ingredient in malathion lotion
  • have severe skin sensitivities
  • are pregnant or breastfeeding

Tell your doctor about all of the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements.



Malathion and Pregnancy

Tell your doctor if you are pregnant or plan to become pregnant.

The FDA categorizes medications based on safety for use during pregnancy. Five categories - A, B, C, D, and X, are used to classify the possible risks to an unborn baby when a medication is taken during pregnancy.

Malathion falls into category B. There are no well-done studies that have been done in humans with malathion. But in animal studies, pregnant animals were given this medication, and the babies did not show any medical issues related to this medication.


Malathion and Lactation

Tell your doctor if you are breastfeeding or plan to breastfeed.

It is not known if malathion crosses into human milk. Because many medications can cross into human milk and because of the possibility for serious adverse reactions in nursing infants with use of this medication, a choice should be made whether to stop nursing or stop the use of this medication. Your doctor and you will decide if the benefits outweigh the risk of using malathion.

Malathion Usage

Take malathion exactly as prescribed.

Malathion comes as a lotion that is applied to the scalp and hair.

One treatment may be effective, but sometimes a second malathion treatment is required. If live lice are seen 7 to 9 days after the first treatment then a second application is necessary.

This lotion should only be applied to hair and scalp. If skin irritation occurs, wash scalp and hair right away. If the irritation does not persist, you can apply malathion Lotion again. If skin irritation occurs again, contact your doctor.

To use malathion lotion, follow these steps:

  1. Be sure to keep your eyes closed during this treatment. 

  2. Apply malathion lotion to dry hair and scalp area paying special attention to area behind your ears and at the back of your neck. Use enough lotion to thoroughly cover hair and the entire scalp area.

  3. Allow hair to air dry. Keep hair uncovered.

  4. Leave the lotion on your hair and scalp for 8 to 12 hours.

  5. After 8 to 12 hours have passed, shampoo your hair and scalp with warm water in a sink. Using the sink is best, instead of a shower or bathtub, because you do not want to get the lotion over the rest of your body.

  6. It is important to wash your hands after the application and rinsing steps.

  7. Use a lice comb to remove the dead lice and nits (empty egg shells) after this treatment. 

  8. If you see live lice on your head 7 to 9 days after treatment, repeat this entire process.

After using malathion lotion, sanitize all the clothing, underwear, pajamas, hats, sheets, pillowcases, and towels you have used recently. These items should be washed in very hot water or dry-cleaned. You should also wash combs, brushes, hairs clips and other personal care items in hot water.

Malathion Dosage

Use malathion lotion exactly as prescribed by your doctor. Follow the directions on your prescription label carefully.

The recommended dose is one application of malation lotion, in an amount necessary to thoroughly wet the hair and scalp.

A second dose (application) may be required if lice are present after 7 to 9 days.


Malathion Overdose

If someone swallows malathion lotion, call your local Poison Control Center or seek emergency medical attention right away.

Other Requirements

  • Store at room temperature between 20° and 25°C (68° - 77°F).
  • Flammable. Keep away from heat and open flame.
  • Keep this and all medications out of the reach of children.