Safety verdict
Consulted references classify the plant as toxic or irritating for that pet type.
Pet ingestion lookup
My cat ate Watercress - what should I do?
Nasturtium officinale
Potentially toxic
Contact your veterinarian or an animal poison-control resource now, especially if any amount was chewed or swallowed.
Verified against ASPCA/provenance audit 2026-05-06 on May 6, 2026.
Signs to watch for
Vomiting, diarrhea, and potential drooling.
Escalation note
Ingestion typically results in mild to moderate gastrointestinal upset. Please contact your veterinarian if your cat consumes a large amount or shows persistent symptoms.
What to watch for
ASPCA lists mild vomiting and diarrhea. Drooling and lip-smacking from the bitter, peppery taste are common. Larger ingestions can produce more pronounced GI signs and dehydration.
Time window
GI signs typically appear within hours of ingestion; mild cases generally resolve within 24–48 hours. Exact onset and duration are not detailed in the ASPCA listing.
When to call the vet
Call your vet or ASPCA Animal Poison Control (888-426-4435) if vomiting or diarrhea persists more than a few hours, your cat refuses food or water, or signs worsen rather than improve. For a single nibble in an otherwise well cat, monitoring is usually enough.
What this means for your cat
Cats — toxic, but mildly. ASPCA lists watercress (Nasturtium officinale) as toxic to cats; the toxic principles are gastrointestinal irritants and the typical reaction is GI upset rather than systemic poisoning. Cats rarely seek out the bitter peppery foliage, so most exposures are incidental — a houseplant brushed past, or a cat investigating a salad bowl.
Sources: ASPCA (no first-aid guidance).
Poison-control resources
This page summarizes source-bound plant-safety information and is not veterinary advice.