Wisteria Poisoning in Dogs

Wisteria (wistaria or wysteria) is a climbing vine related to the flowering pea plant that will wrap around anything and grows up to 60 feet high and 30 feet wide. The flowers grow in flowing bunches of white, pink, violet, or purple. The seedpods are similar to peapods and are the most poisonous with high levels of lectin and wisterin toxins. Both of these can be lethal if seed pods or seeds are eaten, or if a large amount of flowers or foliage is consumed. There is no immediate pain or foul taste so your dog may continue to eat until a fatal amount is consumed so even if there are no symptoms, you should call your veterinarian or go to a veterinary professional as soon as possible.

Wisteria vines are a group of flowering vines that are as dangerous as they are beautiful. While they are known for their flowing waterfall of hanging blooms, they are also known to be poisonous if just a few seed pods are eaten. In fact, fatalities of small animals and children have been reported several times over the years. There are two toxic properties in wisteria; lectin and wisterin glycoside. These can both result in fatalities, but the seed pods and the seeds themselves are the most toxic, containing the highest amounts of both lectin and wisterin glycoside. Lectin results in clumping of the blood cells and produces dangerous blood clotting and possible stroke. The wisterin glycoside can also be fatal by causing severe diarrhea and vomiting that can result in dehydration and death.

The symptoms of wisteria poisoning depend on what part of the plant was eaten and the amount that your dog consumed. As few as three seeds from a wisteria pod can cause gastrointestinal symptoms and more than five can be fatal. 

• Collapse
• Confusion
• Dehydration
• Diarrhea
• Dizziness
• Nausea
• Repeated vomiting
• Severe diarrhea
• Speech problems
• Stomach pains

Types

There are different varieties of wisteria, such as the American wisteria, which is common in the United States, and the Japanese or Chinese wisteria, common in Asia. The flowers range in size from one centimeter to several inches across with either oblong or oval pods. Leaves range in size and amount, but are always a deep green color. The wisteria is in the Fabaceae family of the fabales order in the genus of wisteria. Some of the common and scientific names are:

• American wisteria
• Wistaria
• Wisteria brachybotrys
• Wisteria brevidentata
• Wisteria floribunda
• Wisteria frutescens.
• Wisteria macrostachya
• Wisteria sinensis
• Wisteria venusta
• Wisteria villosa
• Wysteria

There are two toxic principles in wisteria.

• Lectin is a serious toxin that causes diarrhea, headache, nausea, dehydration, confusion, and death by binding to the surfaces of blood cells in the body
• Wisterin glycoside is a saponin sometimes referred to as wistarin or wisterine in the seeds of the wisteria pods that can be lethal if eaten by your dog

Try to bring a sample of the wisteria plant with you so the veterinarian will be able to have it tested to determine the exact species. Even if the test results take a few days, it is best find out in case the treatment or medication needs to be adjusted when the results come back. A thorough examination of your dog will be done including physical appearance, oxygen levels weight, height, body temperature, blood pressure, respiration rate, breath sounds, reflexes, and heart rate.

The veterinarian will need all the details you have about when your dog ate the wisteria and what symptoms you have seen, if any. In addition, your dog’s medical history, vaccination records, and recent illnesses or injuries should be brought to the veterinarian’s attention. A urinalysis, blood count, glucose levels, BUN (blood urea nitrogen), chemistry panel, and blood gases will be performed. Also, if your dog has been vomiting, a PCV (packed cell volume) will be performed to check for dehydration. An ECG (electrocardiogram) can be used to measure the electrical performance of the heart. To get a better view of your dog’s internal organs, an ultrasound, x-rays, and CT scans may be done.

Your dog’s treatment depends on the results of the laboratory tests, ECG, and imaging. The usual procedure includes prompting emesis (vomiting) with a hydrogen peroxide solution, activated charcoal to absorb the toxins, and maybe a gastric lavage with warm saline to clear any leftover toxin residue in the digestive system. Intravenous (IV) fluids will be given for several hours or overnight to flush the toxins from your dog’s kidneys and rehydrate the system.

If treatment is started within 24 hours and your dog did not eat more than one seed pod, the prognosis is good. However, if a large amount of seeds were consumed, the veterinarian will keep your dog hospitalized for observation and supportive treatment for at least 24 hours. Due to the danger to pets and children, be sure to remove any wisteria plants from your property or if this is not possible, securely block that area, denying all access to your children, dog, and other animals.