Are rhododendrons poisonous to dogs?

Updated 11/07/2023

Rhododendrons: found all over the world in a variety of warm and vibrant shades, it’s no wonder they’re found in back gardens here, there and everywhere. If you’ve got furry friends at home though, you’re probably looking for ways to pup-proof your living space and outdoor areas. That’s why here, we’re answering - are rhododendrons toxic to dogs, or can dogs eat rhododendrons? So without any further ado, let’s find out.

Are rhododendrons poisonous to dogs?

Yes, rhododendrons are poisonous to dogs (and humans). Despite their beauty, they can have pretty nasty side effects if your pup’s curiosity takes over and they take a nibble or two. Rhododendrons contain grayanotoxins which are compounds that disrupt sodium channels, affecting the functioning of nerves, muscles and the heart.

The most poisonous part of the rhododendron plant is the leaves, but the flowers and nectar are also bad news for our canine companions if ingested. In fact, even honey made from rhododendron nectar can be dangerous for both humans and dogs, causing dizziness, weakness, sickness and nausea.

Rhododendron poisoning in dogs

Symptoms

If you think your precious pooch has nibbled on so much as a bite from a rhododendron plant, make an appointment with a veterinarian as a matter of emergency. Within the first six hours of ingestion, the most likely initial signs of toxicity are excessive salivation, vomiting and diarrhea, which are followed by further signs such as loss of vision, an inability to stand, weakness, and tremors or seizures. If left untreated, rhododendron poisoning in dogs can lead to death, so it’s vital that they receive medical attention immediately.

A full list of symptoms includes:

Gastrointestinal signs

• Excessive salivation
• Sickness
• Diarrhea
• Tummy pain

Neurological signs

• Depression
• Paralysis
• Loss of vision
• Tremors
• Seizures
• Coma

Cardiac symptoms

• Abnormal heart rhythms
• Hypotension
• Shortness of breath
• Weakness

Ingestion of rhododendron can be fatal if left untreated, even if only eaten in fairly small amounts.

Diagnosis

Like with any ingestion of a plant toxic to dogs, it’s important to act fast. Make an appointment with your veterinarian as soon as you realize what’s happened, even if your pup hasn’t developed symptoms yet - the earlier they receive examination and treatment, the better. If you can, take a sample of the plant with you to your vet - this will help with accurate diagnosis and treatment. During the appointment, your veterinarian will perform a full examination, including listening to your pup’s heart. Further tests may be required, such as blood tests, or an electrocardiogram if any abnormal heart rhythms are detected.

Treatments

It’s important to allow your veterinarian to administer any treatments, as if performed incorrectly, further health problems may follow. Treatments include:

• Inducing vomiting to bring up any undigested plant
• Ingestion of activated charcoal which helps to bind toxins in the gastrointestinal tract
• Intravenous fluids to support the heart, blood pressure, internal organs and to flush through the toxins
• Oxygen
• Medication for specific symptoms such as abnormal heart rhythms, tremors or seizures
•  Your dog may need to be hospitalized for constant veterinary care for a few days 

Meet our veterinary expert, Lizzie

This article has been checked by veterinarian Lizzie Youens BSc (Hons) BVSc MRCVS. Lizzie graduated from the University of Bristol in 2011, and has been working in first opinion companion animal practice. She has worked in a variety of clinics across the UK, from large hospitals to small branch practices. She enjoys doing a mixture of medicine, surgery and emergency work. Lizzie currently works in a small rural practice where she enjoys working in a close-knit community. 

Other plants that are poisonous to dogs

Sadly, many of the plants us humans decorate our gardens and homes with are toxic to dogs, and are in fact poisonous plants dogs should avoid. So, get in the know if your house is home to a curious pup, starting with those below.

• Sweet peas
• Poinsettia
• Sago palm
• Lilies
• Rhubarb