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Is Milk Thistle toxic to cats?

Silybum marianum

Mildly toxic to cats

Mildly. The ASPCA lists milk thistle as mildly toxic to cats — a chewing cat typically gets mouth irritation, drooling, and vomiting rather than a medical emergency, but it is still best kept out of reach. This classification follows the ASPCA Toxic and Non-Toxic Plant List. Not individually listed in the ASPCA toxic/non-toxic plant database. While purified silymarin is sold as a veterinary liver supplement, the raw plant is a documented nitrate accumulator that has caused fatal nitrate poisoning in grazing livestock (notably during wilting). Treat with caution, keep pets from grazing it, and verify with a vet before any deliberate use.

What to do if your cat ate milk thistle

  1. Remove any plant material from your cat's mouth and move milk thistle out of reach.
  2. Note how much was eaten and when, and watch for drooling, vomiting, or lethargy.
  3. Do not induce vomiting unless a vet or poison-control specialist instructs you to.
  4. Call your vet or the ASPCA Animal Poison Control Center on (888) 426-4435 and follow their advice.
  5. Bring a leaf or photo of milk thistle to the appointment so it can be treated correctly.

General guidance, not veterinary advice. If you think your cat has eaten milk thistle, contact your vet or the ASPCA Animal Poison Control Center on (888) 426-4435 — do not wait for symptoms to worsen.

Is milk thistle toxic to cats? — FAQ

Is milk thistle toxic to cats?

Mildly. The ASPCA lists milk thistle as mildly toxic to cats — a chewing cat typically gets mouth irritation, drooling, and vomiting rather than a medical emergency, but it is still best kept out of reach. Not individually listed in the ASPCA toxic/non-toxic plant database. While purified silymarin is sold as a veterinary liver supplement, the raw plant is a documented nitrate accumulator that has caused fatal nitrate poisoning in grazing livestock (notably during wilting). Treat with caution, keep pets from grazing it, and verify with a vet before any deliberate use.

What are the symptoms if a cat eats milk thistle?

Not individually listed in the ASPCA toxic/non-toxic plant database. While purified silymarin is sold as a veterinary liver supplement, the raw plant is a documented nitrate accumulator that has caused fatal nitrate poisoning in grazing livestock (notably during wilting). Treat with caution, keep pets from grazing it, and verify with a vet before any deliberate use. Signs usually appear soon after chewing rather than hours later — watch for drooling, pawing at the mouth, vomiting, loss of appetite, or unusual lethargy after your cat has had access to milk thistle.

What should I do if my cat ate milk thistle?

Stay calm. Remove any plant from your cat's mouth and take the plant away. Note how much was eaten and when, and do not induce vomiting unless told to. Call your vet or the ASPCA Animal Poison Control Center on (888) 426-4435 and follow their advice; a leaf or photo helps the vet treat it correctly.

Is milk thistle toxic to dogs too?

The ASPCA classification Growli uses applies to both cats and dogs: Milk Thistle is mildly toxic to dogs as well. See the full milk thistle pet-safety guide for both species.

What is a cat-safe alternative to milk thistle?

For a similar look without the risk, see the best cats-safe plants list — every plant there is ASPCA non-toxic to cats and dogs.

Full milk thistle pet-safety