What Is Malathion? Uses, Dosage, and What You Need to Know in 2026

If your doctor has prescribed malathion, you may be wondering: what exactly is this medication, and how does it work? This guide covers everything you need to know about malathion — from its FDA-approved uses to how to apply it safely.

What Is Malathion?

Malathion is a prescription topical medication used to treat head lice (Pediculus humanus capitis) and their eggs (nits) in adults and children 6 years and older. It is available under the brand name

Ovide and as a generic (malathion lotion 0.5%). It belongs to a class of drugs called organophosphate pediculicides — medications that kill parasitic insects like lice.

Malathion was first approved by the FDA in 1982. A therapeutically equivalent generic became available in 2009. It is only available by prescription — it cannot be purchased over the counter.

What Is Malathion Used For?

FDA-approved use: Treatment of head lice infestations (Pediculus humanus capitis) in patients 6 years and older.

Off-label uses: The CDC recognizes malathion as an alternative treatment for pubic lice (Pediculus pubis). It has also been used off-label for body lice, though the U.S. formulation — which contains isopropyl alcohol — is generally not recommended for use on genital areas or broken skin.

Malathion is typically prescribed as a

second-line or third-line treatment — meaning it's used when over-the-counter options like permethrin (Nix) or pyrethrin shampoos (Rid) have failed, or when pyrethroid resistance is suspected.

What Makes Malathion Different From OTC Lice Treatments?

Two features distinguish malathion from most OTC lice products:

It's both pediculicidal AND ovicidal. It kills both live lice AND their eggs (nits). Many OTC treatments (like permethrin 1%) only kill live lice and require a second application 7-10 days later to catch newly hatched lice.

It uses a different mechanism. Malathion is an organophosphate — it works differently from pyrethroids. This makes it effective against lice strains that have developed resistance to permethrin and pyrethrin-based products, which is increasingly common across the U.S.

How Do You Apply Malathion? Step-by-Step

Start with DRY hair. Do not shampoo or wet hair before applying malathion.

Apply enough lotion to wet the entire scalp and hair. Pay special attention to the back of the head and nape of the neck where lice tend to concentrate.

Allow hair to air-dry naturally. Do NOT use a hair dryer or any heat source — the lotion is flammable (78% isopropyl alcohol). Leave hair uncovered.

Leave the lotion in for 8 to 12 hours. Most people apply at bedtime and shampoo in the morning.

Shampoo, rinse, and comb. Use a regular (non-medicated) shampoo, rinse thoroughly, then use a fine-toothed nit comb to remove dead lice and eggs.

Check at 7-9 days. If live lice are still present, repeat the treatment once. Additional treatments beyond two are generally not needed.

Who Should NOT Use Malathion?

Neonates and infants (increased scalp permeability increases absorption risk)

Children under 1 year (not recommended)

People allergic to malathion or any ingredient in the vehicle (isopropyl alcohol, terpineol, dipentene, pine needle oil)

Pregnant women — use only if clearly needed; consult prescriber

How Much Does Malathion Cost?

The retail price for malathion 0.5% lotion (one 59 mL bottle) is approximately $250-$260 without insurance. With a GoodRx coupon, the price drops to as low as $76.35 at some pharmacies — about 70% off retail. Most commercial insurance plans and Medicare Part D cover malathion.

Where Can I Get Malathion?

Malathion requires a prescription and must be obtained from a pharmacy. Because most pharmacies don't routinely stock it, finding it can take effort. Use medfinder to find which pharmacies near you have it in stock — medfinder contacts pharmacies on your behalf and texts you the results. See also our detailed guide: How to Find Malathion in Stock Near You.