Safety verdict
Consulted references classify the plant as toxic or irritating for that pet type.
Pet ingestion lookup
My dog 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 abdominal discomfort.
Escalation note
Ingestion can lead to digestive irritation. Always consult a veterinarian if your dog exhibits signs of distress after eating this plant.
First aid at home
Remove any remaining plant material from your dog's mouth and offer fresh water. Do not induce vomiting at home unless a veterinarian or poison-control specialist tells you to — Pet Poison Helpline notes that inducing vomiting without professional guidance can do more harm than good. Then call your vet or ASPCA Animal Poison Control (888-426-4435).
What to watch for
Mild vomiting and diarrhea are the signs ASPCA documents. Watch also for reduced appetite or lethargy in the hours after ingestion. Symptoms usually stay confined to the digestive tract.
Time window
Onset and duration are not well documented for watercress specifically; gastrointestinal irritants generally produce signs within a few hours and resolve in 24–48 hours with supportive care.
When to call the vet
Call your vet or ASPCA Animal Poison Control (888-426-4435) if vomiting or diarrhea is severe, bloody, lasts more than a few episodes, or if your dog seems weak or dehydrated. A small mouthful that produces a single bout of vomiting and otherwise normal behavior is rarely an emergency, but a phone consult is still the safest call.
What this means for your dog
Dogs that nibble watercress usually get away with a queasy stomach rather than a true emergency. ASPCA lists the plant as toxic to dogs, but the toxic principles are gastrointestinal irritants and signs are typically mild — not the kind of cardiac or neurological reaction you see with truly dangerous plants.
Sources: ASPCA, Pet Poison Helpline.
Source references
Poison-control resources
This page summarizes source-bound plant-safety information and is not veterinary advice.