Autumn Crocus poisoning in dogs and cats
Toxic agent: Colchicine · Reviewed 2026-08-18
Phone a vet now, before reading on. Have ready: your pet's weight, roughly how much was eaten and when, and the packaging if there is any. ASPCA Animal Poison Control (+1 888 426 4435), Pet Poison Helpline, or Animal PoisonLine in the UK.
Autumn crocus contains colchicine, the same drug used for gout, and it stops cells dividing. That means the damage lands days later on the fastest-dividing tissues: gut lining and bone marrow.
What it actually does
Colchicine binds tubulin and arrests mitosis. Tissues that renew constantly suffer first — the intestinal lining sloughs, and the bone marrow stops producing blood cells. That is why the serious phase is delayed by days and why an animal that looked recovered can crash in the second week.
How much matters
Every part of the plant is toxic, and the bulb most of all:
| Bulbs (corms) | highest colchicine concentration — dogs dig them up in autumn |
|---|---|
| Leaves and flowers | toxic, and the leaves appear in spring without flowers |
| Often confused with | spring crocus (Crocus species), which causes only mild upset — the two are unrelated plants |
| Also confused with | wild garlic, because the spring leaves look similar |
Colchicum autumnale is the plant that matters. If you can bring a leaf or a photograph, do — the identification changes the level of concern completely.
What you will see, and when
Onset: 2 to 12 hours for gastrointestinal signs; marrow effects at 3–7 days. Typical course: Up to two weeks of monitoring.
- 2–12 hoursDrooling, vomiting, bloody diarrhoea, abdominal pain
- 1–3 daysApparent improvement, dehydration, liver and kidney values rising
- 3–7 daysBone marrow suppression — anaemia, low white cells, bleeding; multi-organ failure in severe cases
What the vet will do
Decontamination early, then intensive supportive care: fluids, gastroprotection, and repeated complete blood counts for a week or more to catch the marrow crash. There is no antidote.
Outlook
Guarded. Large ingestions, particularly of bulbs, can be fatal despite treatment.
Dogs and cats are not the same here
Both. Dogs are the usual patient because they dig.
Where it comes from in a normal house
- Autumn borders and lawns, flowering September to November
- Bulbs bought for planting, stored in sheds
- Grazing paddocks — also toxic to horses and livestock
- Spring meadows, where the leaves come up alone
The thing people get wrong
“It is a crocus, and crocuses are harmless.”
Spring crocus and autumn crocus are different plants from different families. The spring one causes mild stomach upset; the autumn one contains colchicine and can suppress bone marrow. The season it flowers in is the clue.
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Get PawLife on the App StoreFrequently asked questions
How much Autumn Crocus is dangerous?
Colchicum autumnale is the plant that matters. If you can bring a leaf or a photograph, do — the identification changes the level of concern completely.
How long after exposure to Autumn Crocus do symptoms start?
2 to 12 hours for gastrointestinal signs; marrow effects at 3–7 days. Drooling, vomiting, bloody diarrhoea, abdominal pain. Up to two weeks of monitoring.
Is Autumn Crocus worse for cats or dogs?
Both. Dogs are the usual patient because they dig.
Is it true that: It is a crocus, and crocuses are harmless.
Spring crocus and autumn crocus are different plants from different families. The spring one causes mild stomach upset; the autumn one contains colchicine and can suppress bone marrow. The season it flowers in is the clue.
Related emergencies
Sources
This page is information, not veterinary advice. Toxic doses vary with body weight, age, breed and individual sensitivity, and the figures above exist to explain what a vet is assessing, never to decide that an amount is safe. If you are reading this because something has already been eaten, call a vet.