Summary of Use during Lactation

Malathion appears to be poorly absorbed after topical application, so it is not likely to reach the breastmilk in large amounts. Some guidelines consider it a second-choice alternative for the treatment of scabies in nursing mothers.[1]

Drug Levels

The manufacturer reports that 8% of a topically applied solution of malathion (concentration unspecified) in an acetone vehicle is absorbed through human skin. However, the extent of absorption from commercial 0.5% malathion lotion is not known.

Maternal Levels. Nine breastmilk samples were analyzed from women who lived in an area of California that had been sprayed in 1981 with malathion from 4 to 14 times during their pregnancy and lactation. Malathion was undetectable (<5 mcg/L) in all of the samples. Any exposure of the women would probably have been via inhalation or direct ingestion.[2]

Twelve donors from Bhopal, India provided hindmilk samples to monitor for malathion. The mean malathion level in the samples was 0.043 mg/L (range 0 to 0.086 mg/L). The calculated daily intake by breastfed infants was 40% higher than the World Health Organization recommended average daily intake. The source of malathion was thought to be from contaminated food crops that had been harvested before the recommended waiting time after spraying.[3]

Infant Levels. Relevant published information was not found as of the revision date.

Effects in Breastfed Infants

Relevant published information was not found as of the revision date.

Effects on Lactation and Breastmilk

Relevant published information was not found as of the revision date.

Alternate Drugs to Consider

Ivermectin, Permethrin, Pyrethrins

References

1.

Morris G, Haddow L, Sashidharan PN, et al. British Association for Sexual Health and HIV National Guideline on the Management of Scabies in adults 2025. Int J STD AIDS 2025;36:516–32. [PubMed: 40103364]

2.

Lönnerdal B, Asquith MT. Malathion not detected in breast milk of women living in aerial spraying areas. N Engl J Med 1982;307:439. [PubMed: 7088119]

3.

Sanghi R, Pillai MK, Jayalekshmi TR, et al. Organochlorine and organophosphorus pesticide residues in breast milk from Bhopal, Madhya Pradesh, India. Hum Exp Toxicol 2003;22:73–6. [PubMed: 12693830]

Substance Name

Malathion

CAS Registry Number

121-75-5

Drug Class

Breast Feeding

Lactation

Milk, Human

Anti-Infective Agents

Antiparasitic Agents

Insecticides