Thiamethoxam

MedEd Pesticide lists Thiamethoxam as an insecticide in the neonicotinoid class.

MedEd Pesticide Summarizes Thiamethoxam at a Glance

Type

Insecticide

Chemical class

Neonicotinoid

CAS number

153719-23-4

Formula

C8H10ClN5O3S

Molar mass

291.72 g/mol

EU status

Not approved as an active substance in the EU.

US status

Registered with EPA. 95 active products contain Thiamethoxam.

MedEd Pesticide Summarizes Thiamethoxam’s Toxicity Records

MedEd Pesticide holds 174 toxicity records for Thiamethoxam, from 6 sources. The headline values are below.

Oral LD50 in ratsAcute, swallowed

Lowest reported 871 mg/kg, median 871 mg/kg, from 1 record.

Dermal LD50Acute, skin contact

Lowest reported 2000 mg/kg, median 2000 mg/kg, from 1 record.

Lowest NOAELLong term, mammals

0.61 mg/kg-day in rat. Source: ToxRefDB.

EPA signal wordsActive US products

Danger 0, Warning 10, Caution 82.

See all 174 Thiamethoxam toxicity records in the explorer. The records come from EPA’s Toxicity Values Database, and the methodology explains their limits.

MedEd Pesticide Reports Thiamethoxam’s EU Safety Reference Values

MedEd Pesticide takes these values from the EU, which sets them when it assesses an active substance. They are expressed per kilogram of body weight.

ADIAcceptable daily intake

0.026 mg/kg bw/dayThe amount a person can take in every day over a lifetime without appreciable health risk.

ARfDAcute reference dose

0.5 mg/kg bwThe amount that can be taken in over a short period, such as one meal or one day, without appreciable health risk.

AOELAcceptable operator exposure level

0.08 mg/kg bw/dayThe level of exposure for people who apply the pesticide at which no adverse effect is expected.

MedEd Pesticide Lists Thiamethoxam’s EU Hazard Classification

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

• H302 Harmful if swallowed
• H400 Very toxic to aquatic life
• H410 Very toxic to aquatic life with long-lasting effects

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 Thiamethoxam with another pesticide.

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