Is Marsilea quadrifolia toxic to cats?

Mildly. The ASPCA lists marsilea quadrifolia 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. Marsilea quadrifolia is not individually listed in the ASPCA toxic/non-toxic plant database, so its pet status is not formally established; treat with caution and verify with a vet. Marsilea species are noted to contain thiaminase (a vitamin B1-destroying enzyme), which has caused poisoning in livestock that graze them heavily, so this plant should not be assumed pet-safe and grazing should be prevented.

Marsilea quadrifolia is not individually listed in the ASPCA toxic/non-toxic plant database, so its pet status is not formally established; treat with caution and verify with a vet. Marsilea species are noted to contain thiaminase (a vitamin B1-destroying enzyme), which has caused poisoning in livestock that graze them heavily, so this plant should not be assumed pet-safe and grazing should be prevented. 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 marsilea quadrifolia.

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.

The ASPCA classification Growli uses applies to both cats and dogs: Marsilea quadrifolia is mildly toxic to dogs as well. See the full marsilea quadrifolia pet-safety guide for both species.

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.