malathion (Ovide)

  • Pharmacy Author:
    Omudhome Ogbru, PharmD

    Dr. Ogbru received his Doctorate in Pharmacy from the University of the Pacific School of Pharmacy in 1995. He completed a Pharmacy Practice Residency at the University of Arizona/University Medical Center in 1996. He was a Professor of Pharmacy Practice and a Regional Clerkship Coordinator for the University of the Pacific School of Pharmacy from 1996-99.

  • Medical and Pharmacy Editor: Jay W. Marks, MD
    Jay W. Marks, MD

    Jay W. Marks, MD

    Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.

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Malathion is flammable


  • Lotion: 0.5%



  • Malathion has not been adequately evaluated in pregnant women. Available data from animals suggests that the risk of fetal toxicity is low. It should be used (or handled) during pregnancy only if clearly needed.
  • It is not known whether malathion is excreted in breast milk.


  • Malathion should be stored at room temperature, 20 C - 25 C (68 F - 77 F). It is flammable and should be kept away from heat and open flame.


  1. Dry hair and scalp should be thoroughly wet with malathion lotion, including the back of the head and neck. The hands should be washed after applying.
  2. The hair should not be covered and should dry naturally without using an electric heat source.
  3. The hair should be shampooed after 8 to 12 hours, rinsed and combed with a fine - toothed (nit) comb to remove dead lice and eggs.
  4. Malathion lotion should be applied again if lice are still present after 7 - 9 days.


  • Malathion is a pesticide used for killing head lice (Pediculus humanus capitis). It kills head lice and lice eggs by blocking the activity of enzymes (cholinesterase) that breaks-down and inactivates acetylcholine (a neurotransmitter) in head lice. This causes high levels of acetylcholine which leads to death of lice.
  • The FDA approved malathion in August, 1982.

REFERENCE: FDA Prescribing Information

Medically Reviewed by a Doctor on 4/6/2016

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