Arrowhead Vine Poisoning in Dogs

The Arrowhead vine plant has spade-shaped leaves with varying cream and white marking on them. They are generally cultivated as houseplants but have also been naturalized in areas of Florida, Texas, and Hawaii. All portions of the Arrowhead vine plant contain insoluble calcium oxalate crystals. These crystals will cause intense pain and irritation when chewed or swallowed. The irritation and swelling caused by the crystal usually inhibit animals from doing more than sampling the plant. On rare occasions, dogs may swallow larger amounts of plant material. On those occasions, your canine companion may require a visit to the veterinarian’s office for additional treatment.

The Arrowhead vine plant is one of several that contain calcium oxalate crystals which cause intense pain and irritation to the mouth and gastrointestinal tract when chewed or swallowed.

Arrowhead vine plants contain insoluble calcium oxalate crystals in the cells of the plant. When chewed or swallowed these crystals can cause symptoms such as: 

• Cardiac arrhythmia
• Diarrhea
• Dilated eyes 
• Difficulty swallowing
• Excessive drooling
• Hoarse barking
• Labored breathing
• Loss of appetite
• Numbness of exposed area
• Obstruction of the airway
• Pawing/rubbing at the face or mouth
• Swelling of the lips or tongue
• Vocalization
• Vomiting

Some species may cause additional inflammation from proteinase that increases swelling by instigating the release of histamines.  

Types

The Arrowhead vine (Syngonium podophyllum) is also known as African Evergreen, American Evergreen, Goosefoot plant, Nephthytis, and Trileaf wonder. There are several other plants that contain the same calcium oxalate crystals which cause the irritation and swelling from Arrowhead vine plants. These plants can include: 

• Calla or arum lily (Zantedeschia aethiopica)
• Chinese evergreen (Aglaonema modestrum)
• Devil’s ivy (Pothos, Epipremnum)
• Dumbcane (Dieffenbachia)
• Elephant’s Ear (Alocasia/Caladium/Xanthosoma)
• Fruit salad plant (Monstera)
• Jack-in-the-pulpit (Arisaema triphyllum)
• Peace lily (Spathiphyllum)
• Philodendron (Philodendron)
• Rhubarb (Rheum rhabarbarum)
• Skunk cabbage (Symplocarpus foetidus)
• Wild calla (Calla)

Every part of the Arrowhead vine plant contains the calcium oxalate crystals that cause the pain and inflammation. Calcium oxalate is a calcium salt of oxalic acid which produces irritation or numbness to the tissues it comes in contact with. Chewing any part of the plant may cause immediate pain and inflammation to the mouth and throat area as the crystals embed themselves into the soft tissues. If any of the sap or plant material is actually swallowed the irritation can extend to the throat and down into the GI tract, causing internal swelling and severe pain. Breathing difficulty may also occur if swelling in the throat has blocked the airway.

Many of the symptoms of exposure to the calcium oxalate crystals from the Arrowhead vine will present immediately so plant identification is often all that is required for diagnosing the origin of your pet’s distress. Although many symptoms are instantaneous, other symptoms can take up to two hours to appear. If you did not observe what your pet ingested or if your dog ingested large amounts of the plant material your veterinarian may recommend a visit to the office. Your veterinarian will want to take special note any opportunistic eating in addition to any concurrent prescriptions or supplements that your dog is taking. A complete blood count, biochemistry profile, and urinalysis likely to be done at this time as well in order to point out any concurrent disorders or diseases. If your dog has ingested enough of the plant material that vomiting is occurring, then the vomitus will also be examined and tested for toxins. Plant material found in the vomit may help confirm the diagnosis.

Initial treatment will begin with a thorough rinsing of the mouth and affected areas with clean water to remove as many of the crystals from the skin and soft tissues as possible. You may want to offer your dog something cool to eat or drink to ease the pain until you are able to contact your veterinarian. In most cases, the discomfort and unpleasant taste will prevent most canines from ingesting much of the actual plant material and so rinsing the mouth area may be all the treatment that is required. In certain circumstances, your veterinarian will recommend an appropriate pain reliever or antihistamine to give your dog as well.

If a larger amount of the plant material or sap was ingested a visit to the veterinarian’s office may be encouraged. IV fluid treatment will be most likely given at the veterinarian’s office to prevent dehydration and if an antihistamine was not previously administered it may be administered at this time as an intramuscular injection. Gastro-protective medications may also be recommended to prevent damage to the lining of the stomach. If the airway is swollen enough to cause any sort of blockage, your canine may need to be kept under observation at the office until the swelling subsides.

The prognosis for dogs affected by ingesting smaller amounts of the plants containing the calcium oxalate crystals, such as the arrowhead vine, is usually quite good. The effects of the crystals in the mouth and gastrointestinal tract usually disappear or diminish within twelve to twenty-four hours from ingestion. Any swelling in the airway should be evaluated by a veterinarian and may alter the prognosis. Massive doses of the plant are rare due to the initial pain and discomfort in the mouth. When larger doses do occur they can cause long-term liver and kidney damage so the liver and kidneys may need more regular monitoring after the ingestion of substantial quantities of plant material.