Is Colchicine safe for dogs and cats?
High risk for petsDogs are at risk from colchicine toxicity through two primary exposure pathways: ingestion of autumn crocus or glory lily plant material (more common in outdoor dogs with garden access), and accidental ingestion of owner's colchicine tablets (the pharmaceutical drug is commonly prescribed for gout). The autumn crocus (Colchicum autumnale) produces flowers in late summer/autumn that are attractive to dogs; all parts are toxic. Clinical signs include profuse hemorrhagic GI signs, followed by bone marrow suppression (leukopenia, thrombocytopenia appearing 3–5 days post-ingestion), sepsis from myelosuppression, and multi-organ failure. ASPCA Animal Poison Control Center ranks Colchicum plants as causing severe toxicosis in dogs, with prognosis depending heavily on dose and timing of treatment. Decontamination within 1–2 hours of ingestion followed by intensive supportive care (IV fluids, antimicrobials, G-CSF, blood products for myelosuppression) offers the best survival chance.
What is colchicine?
The IUPAC name is N-[(7S)-1,2,3,10-tetramethoxy-9-oxo-6,7-dihydro-5H-benzo[a]heptalen-7-yl]acetamide.
Also known as: N-[(7S)-1,2,3,10-tetramethoxy-9-oxo-6,7-dihydro-5H-benzo[a]heptalen-7-yl]acetamide, Colchisol, Colchineos, Colchicinum.
- IUPAC name
- N-[(7S)-1,2,3,10-tetramethoxy-9-oxo-6,7-dihydro-5H-benzo[a]heptalen-7-yl]acetamide
- CAS number
- 64-86-8
- Molecular formula
- C22H25NO6
- Molecular weight
- 399.4 g/mol
- SMILES
- CC(=O)NC1CCC2=CC(=C(C(=C2C3=CC=C(C(=O)C=C13)OC)OC)OC)OC
- PubChem CID
- 6167
Risk for dogs
High riskDogs are at risk from colchicine toxicity through two primary exposure pathways: ingestion of autumn crocus or glory lily plant material (more common in outdoor dogs with garden access), and accidental ingestion of owner's colchicine tablets (the pharmaceutical drug is commonly prescribed for gout). The autumn crocus (Colchicum autumnale) produces flowers in late summer/autumn that are attractive to dogs; all parts are toxic. Clinical signs include profuse hemorrhagic GI signs, followed by bone marrow suppression (leukopenia, thrombocytopenia appearing 3–5 days post-ingestion), sepsis from myelosuppression, and multi-organ failure. ASPCA Animal Poison Control Center ranks Colchicum plants as causing severe toxicosis in dogs, with prognosis depending heavily on dose and timing of treatment. Decontamination within 1–2 hours of ingestion followed by intensive supportive care (IV fluids, antimicrobials, G-CSF, blood products for myelosuppression) offers the best survival chance.
Risk for cats
Extreme riskCats appear more sensitive to colchicine toxicity than dogs, and the glory lily (Gloriosa superba) — increasingly popular as an ornamental plant — has caused documented cases of severe colchicine poisoning in cats in the UK and Europe. All parts of Gloriosa are toxic, including pollen that can contaminate a cat's coat through grooming after brushing against the plant. Clinical signs in cats include rapid-onset GI hemorrhage, neurological signs, hypothermia, and multi-organ failure that can progress to death within 24–72 hours of ingestion. ASPCA and the UK Veterinary Poisons Information Service list glory lily and autumn crocus as causing severe, potentially fatal toxicosis in cats. Prognosis for cats with multi-organ failure from colchicine is poor; early decontamination is critical.
Regulatory consensus
3 regulatory and scientific bodies have classified Colchicine. The classifications differ — that's the data.
| Agency | Year | Classification | Notes |
|---|---|---|---|
| IARC | 1993 | Group 3 (not classifiable as to carcinogenicity to humans) | Evaluated as an antimitotic alkaloid; inadequate evidence in humans and animals for carcinogenicity classification. Primary toxicological concern is acute multi-organ toxicity via tubulin binding and bone marrow suppression, not carcinogenicity. |
| EPA CTX / Genetox | — | Genotoxicity: positive (Ames: negative, 6 positive / 3 negative reports) | |
| EPA CTX / Genetox | — | Genotoxicity: positive (Ames: negative, 6 positive / 3 negative reports) |
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 colchicine
- Industrial Facilities — Manufacturing plants, Chemical storage areas, Waste treatment sites
- Occupational Environments — Factories, Warehouses, Transportation vehicles
Safer alternatives
Lower-risk approaches that achieve a similar outcome to Colchicine:
-
Avoidance (no chemical substitute)
Trade-offs: Direct chemical substitution requires verification that the replacement does not introduce new hazards (regrettable substitution). Conduct full hazard assessment of proposed alternative before adoption.Relative cost: 1.2-2×
Frequently asked questions
Is colchicine safe for pets?
Dogs are at risk from colchicine toxicity through two primary exposure pathways: ingestion of autumn crocus or glory lily plant material (more common in outdoor dogs with garden access), and accidental ingestion of owner's colchicine tablets (the pharmaceutical drug is commonly prescribed for gout). The autumn crocus (Colchicum autumnale) produces flowers in late summer/autumn that are attractive to dogs; all parts are toxic. Clinical signs include profuse hemorrhagic GI signs, followed by bone marrow suppression (leukopenia, thrombocytopenia appearing 3–5 days post-ingestion), sepsis from myelosuppression, and multi-organ failure. ASPCA Animal Poison Control Center ranks Colchicum plants as causing severe toxicosis in dogs, with prognosis depending heavily on dose and timing of treatment. Decontamination within 1–2 hours of ingestion followed by intensive supportive care (IV fluids, antimicrobials, G-CSF, blood products for myelosuppression) offers the best survival chance.
What products contain colchicine?
Colchicine appears in: Manufacturing plants (Industrial facilities); Chemical storage areas (Industrial facilities); Factories (Occupational environments); Warehouses (Occupational environments).
Why do regulators disagree about colchicine?
Colchicine has been classified by 3 agencies including IARC, EPA CTX / Genetox, EPA CTX / Genetox, with differing conclusions. 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. See the regulatory consensus table on this page for the full picture.
See Colchicine in the pets app
Look up products containing colchicine, compare to alternatives, and explore the full data record.
Open in pets View raw API dataSources (3)
- IARC Monographs Volume 56: Some Naturally Occurring Substances — Food Items, Heterocyclic Amines and Mycotoxins; Colchicine Evaluation, Group 3 Classification (1993) (1993) — regulatory
- US FDA: Colchicine — Drug Safety Communication on Narrow Therapeutic Index, Overdose Risk, Drug Interactions (Colcrys), and Toxicokinetics (2012) (2012) — regulatory
- ASPCA Animal Poison Control Center: Autumn Crocus (Colchicum autumnale) and Glory Lily (Gloriosa superba) — Colchicine Toxicity in Dogs and Cats, Multi-Stage Clinical Presentation and Case Outcomes (2021) — veterinary
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 →