Pet Safety / Compounds / Mecoprop (MCPP)

Is Mecoprop (MCPP) safe for dogs and cats?

Moderate risk for pets

Not veterinary or professional safety advice, and not a substitute for a veterinarian — consult one about your animal. Full disclaimer →

Dogs are commonly exposed to mecoprop through treated lawns. Dogs are more sensitive to phenoxy herbicides than other species. GI irritation, diarrhea, and in severe cases, myotonia have been reported.

What is mecoprop (mcpp)?

The IUPAC name is 2-(4-chloro-2-methylphenoxy)propanoic acid.

Also known as: MCPP, Mecoprop-P, Methylchlorophenoxypropionic acid, Kilprop.

IUPAC name
2-(4-chloro-2-methylphenoxy)propanoic acid
CAS number
7085-19-0
Molecular formula
C10H11ClO3
Molecular weight
214.65 g/mol
SMILES
CC1=C(C=CC(=C1)Cl)OC(C)C(=O)O
PubChem CID
7153

Risk for dogs

Moderate risk

Dogs are commonly exposed to mecoprop through treated lawns. Dogs are more sensitive to phenoxy herbicides than other species. GI irritation, diarrhea, and in severe cases, myotonia have been reported.

Regulatory consensus

2 regulatory and scientific bodies have classified Mecoprop (MCPP). The classifications differ — that's the data.

AgencyYearClassificationNotes
IARC2015Group 2B — Possibly carcinogenic to humans
EU2003Approved (mecoprop-P only); racemic mecoprop not approved

Regulators apply different standards of evidence — animal-data weighting, exposure-pattern assumptions, epidemiological power thresholds — which is why two scientific bodies can review the same data and reach different conclusions. The disagreement is the data.

Where pets encounter mecoprop (mcpp)

  • Lawn Care
  • Water
  • Building Materials

Safer alternatives

Lower-risk approaches that achieve a similar outcome to Mecoprop (MCPP):

  • Iron-based herbicides (FeHEDTA)
    Trade-offs: Slower activity, requires repeat applications. Only effective on certain broadleaf species. No systemic activity.
    Relative cost: Higher per application
  • Manual weed removal / cultural practices
    Trade-offs: Labor-intensive but eliminates chemical exposure entirely.
    Relative cost: Labor cost only

Frequently asked questions

Is mecoprop (mcpp) safe for pets?

Dogs are commonly exposed to mecoprop through treated lawns. Dogs are more sensitive to phenoxy herbicides than other species. GI irritation, diarrhea, and in severe cases, myotonia have been reported.

See Mecoprop (MCPP) in the pets app

Look up products containing mecoprop (mcpp), compare to alternatives, and explore the full data record.

Open in pets View raw API data

Sources (2)
  1. IARC Monograph Vol. 113 — DDT, Lindane, and 2,4-D (2015) — iarc
  2. EPA Reregistration Eligibility Decision — MCPP — epa

Reference data, not professional advice. Aggregates publicly available regulatory and scientific data; not a substitute for veterinary, medical, legal, or regulatory advice. Why we built ALETHEIA →