Are Rhododendrons Poisonous to Dogs?

All parts of a rhododendron bush—the leaves, stems and blooms—are toxic to dogs. Only a small amount of rhododendron is needed to cause health problems if your dog eats part of the plant. Small dogs will typically experience more severe toxic effects than large dogs eating the same amount of rhododendron.

The toxic chemical in rhododendrons is grayantoxin. This neurotoxin affects the body's nerve cells. Horses and cats, like dogs, are susceptible to the poisonous effects of grayantoxin.

If your dog eats part of a rhododendron plant, symptoms will usually start to be noticeable between one and three hours later. The most common symptoms of rhododendron poisoning in a dog include gastrointestinal upset, fatigue, loss of appetite, excess saliva, general weakness, weakened pulse, paralysis of the legs and depression. Your dog may exhibit other symptoms too. Following these initial symptoms, more serious effects may appear—these include significant diarrhea, vomiting and low blood pressure. Symptoms may progress until a dog's cardiovascular and central nervous systems shut down—coma and death may follow.

If your dog shows any signs of rhododendron poisoning, seeking immediate veterinary help could be lifesaving. Call a vet or take your dog to a veterinary clinic immediately. Your veterinarian may administer medications that can help alleviate toxic effects of the rhododendrons. Life support may also be an option to help your pet stay alive.