Permethrin

MedEd Pesticide lists Permethrin as an insecticide in the pyrethroid class.

MedEd Pesticide Summarizes Permethrin at a Glance

Type

Insecticide

Chemical class

Pyrethroid

CAS number

52645-53-1

Formula

C21H20Cl2O3

Molar mass

391.3 g/mol

EU status

Not approved as an active substance in the EU.

US status

Registered with EPA. 540 active products contain Permethrin.

MedEd Pesticide Summarizes Permethrin’s Toxicity Records

MedEd Pesticide holds 281 toxicity records for Permethrin, from 7 sources. The headline values are below.

Oral LD50 in ratsAcute, swallowed

Lowest reported 220 mg/kg, median 301.5 mg/kg, from 2 records.

Dermal LD50Acute, skin contact

Lowest reported 1750 mg/kg, median 1875 mg/kg, from 2 records.

Lowest NOAELLong term, mammals

5 mg/kg-day in dog, 52 weeks. Source: ToxRefDB.

EPA signal wordsActive US products

Danger 11, Warning 56, Caution 462.

See all 281 Permethrin toxicity records in the explorer. The records come from EPA’s Toxicity Values Database, and the methodology explains their limits.

MedEd Pesticide Reports Permethrin’s EU Safety Reference Values

MedEd Pesticide finds no safety reference values for Permethrin in the EU database.

MedEd Pesticide Lists Permethrin’s EU Hazard Classification

MedEd Pesticide lists the harmonised EU hazard statements for Permethrin below.

• H302 Harmful if swallowed
• H332 Harmful if inhaled
• H400 Very toxic to aquatic life
• H410 Very toxic to aquatic life with long-lasting effects
• H335 May cause respiratory irritation

MedEd Pesticide takes EU status, reference values and hazard classification from the EU Pesticides Database. MedEd Pesticide takes US status from EPA’s Pesticide Product Information System (dated 2026-10-13) and chemical identity from PubChem. Retrieved 2026-10-16. Values and approvals change, so check the source for the current entry. See the methodology and the glossary, or compare Permethrin with another pesticide.

MedEd Pesticide. (2026). Permethrin. https://mededpesticide.org/pesticides/permethrin/ (accessed Month Day, Year)