Is Alisma plantago-aquatica toxic to dogs?

Mildly. The ASPCA lists alisma plantago-aquatica as mildly toxic to dogs — a chewing dog typically gets mouth irritation, drooling, and vomiting rather than a medical emergency, but it is still best kept out of reach. Alisma plantago-aquatica is not individually listed by the ASPCA as toxic or non-toxic; treat with caution and verify with a vet. The fresh plant contains acrid saponin-type compounds that can cause gastrointestinal upset and skin/mouth irritation (the foliage is only made edible for humans by thorough cooking or drying), so do not let cats or dogs graze it.

Alisma plantago-aquatica is not individually listed by the ASPCA as toxic or non-toxic; treat with caution and verify with a vet. The fresh plant contains acrid saponin-type compounds that can cause gastrointestinal upset and skin/mouth irritation (the foliage is only made edible for humans by thorough cooking or drying), so do not let cats or dogs graze it. 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 dog has had access to alisma plantago-aquatica.

Stay calm. Remove any plant from your dog'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 in the US, or Animal PoisonLine on 01202 509 000 in the UK 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: Alisma plantago-aquatica is mildly toxic to cats as well. See the full alisma plantago-aquatica pet-safety guide for both species.

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