Suspect poisoning? US: ASPCA Poison Control (888) 426-4435 · UK: 01202 509 000 · Severe symptoms → nearest emergency vet now.

How soon will a dog show signs after chewing Dieffenbachia?

Dogs · Emergency guide

Last reviewed: 2026-09-05 · Reference ranges: ASPCA, Pet Poison Helpline & Merck Veterinary Manual

Short answer

Immediately. The calcium oxalate crystals cause instant burning pain, drooling and pawing at the mouth. Swelling peaks within 2 hours — watch closely for trouble breathing as throat inflammation can block airways. Rinse the mouth with cool water or milk and call your vet now if you see facial swelling or noisy breathing. For severe reactions, contact the ASPCA poison line at 888-426-4435 on your way to the clinic.

Why is this dangerous?

The plant is packed with insoluble calcium oxalate crystals (raphides). When chewed they shoot into the soft tissue of the mouth and release histamine-like compounds, causing immediate, intense burning and swelling.

It is rarely fatal, but swelling of the tongue and throat can occasionally block the airway — that is the emergency to watch for.

Why speed matters

Delaying care significantly worsens outcomes. Some signs appear hours or days later, so "looks fine right now" is not a reason to wait.

Signs to watch for

  • Sudden intense drooling and pawing at the mouth
  • Swollen lips, tongue or muzzle
  • Yelping, head shaking, refusing food
  • Vomiting shortly after chewing
  • Trouble breathing, noisy or raspy breathing (emergency)

What to do right now

  1. Rinse the mouth with cool water or offer milk or plain yoghurt — dairy can ease the burning.
  2. Do not give anything acidic and do not try to pull plant material out of the throat.
  3. Call the vet; if the face is swelling or breathing is noisy, go now.
  4. Move the plant out of reach or rehome it — this is the most common household plant poisoning.
If your pet shows any of the signs above, go to the nearest emergency vet now and call ahead.

The step-by-step response, from the first minute to the vet visit, is in our Dieffenbachia (Dumb Cane) emergency guide.

Open the full emergency guide: Dieffenbachia (Dumb Cane) →