Chinese Evergreen Poisoning in Dogs

Aglaonema, commonly known as the Chinese evergreen, is an evergreen perennial that can either creep across the ground or grow erect and has a crown of variegated broad silver and green leaves. It does not tolerate the cold well and will develop dark, greasy patches where cold damage has occurred. For this reason, it is usually found indoors as a houseplant. All parts of the Chinese evergreen contain insoluble calcium oxalate crystals and these crystals are known for causing intense pain and irritation when chewed or swallowed. This irritation usually prevents animals from doing more than sampling the plant. On rare occasions, the dog may swallow more considerable amounts of plant material. If that occurs your canine companion may require a visit to your veterinarian’s office.

The Chinese evergreen (Aglaonema modestrum) contains calcium oxalate crystals which can cause intense pain and swelling in the mouth and gastrointestinal tract of your pet when chewed or swallowed, prompting the need for a veterinary visit.

The Araceae family of plants often contain insoluble calcium oxalate crystals in all parts of the plant. When chewed or swallowed these crystals can cause: 

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

Types

The Aglaonema modestrum plant has been grown in Asia for centuries as a good luck plant and is often grown as an attractive houseplant. It is a tropical plant and well known for intolerance to cold and can sustain injury at just 59 degrees Fahrenheit, so it is not generally found in the outdoor gardens of North America. 

• Arrowhead vine (Syngonium podophyllum)
• Calla or arum lily (Zantedeschia aethiopica)
• Candelabra cactus (Euphorbia lactea)
• Devil’s ivy (Pothos, Epipremnum)
• Dumbcane (Dieffenbachia)
• Elephant’s ear (Alocasia/Caladium/Xanthsoma)
• Flamingo plant (Anthurium)
• 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)

All parts of the Chinese evergreen contain the calcium oxalate crystals that cause the distress. Calcium oxalate is a calcium salt of oxalic acid which creates pain and irritation to any soft tissues that it comes in contact with. Chewing on this plant will cause immediate pain and inflammation to the mouth and throat area as these crystals are embedded into the soft tissues of the mouth. If any of the plant material or sap is swallowed the irritation can extend to the throat and down through the GI tract, causing severe swelling and pain. The swelling may block the airway, causing difficulty breathing, and in rare cases, death.

Many of the symptoms of exposure to the calcium oxalate crystals from the Chinese evergreen will present immediately so identification of the plant is often all that is necessary for diagnosing the cause of the disturbance. Occasionally symptoms will take longer to appear, up to two hours. Symptoms have been known to take up to two hours to show up. If you did not observe what your pet ingested, or if your dog ingested considerable quantities of the plant material, your veterinarian may recommend a visit to the office. The veterinarian will ask you questions regarding any opportunistic eating, in addition to getting information about any concurrent supplements or prescriptions that your dog is on. A complete blood count, biochemistry profile, and urinalysis will likely be done at this point as well. If your dog has ingested enough of the plant material that they are vomiting, then the vomitus will also be examined and tested for toxins. Plant material in the vomit may help confirm the diagnosis.

Immediate treatment will start with a meticulous rinsing of the mouth and affected areas with cool, clean water to remove as many of the microscopic crystals as possible. You may also want to offer your dog ice chips in his water bowl, to ease the pain in their mouth until you are able to contact your veterinarian. The discomfort and unpleasant taste will usually prevent most canines from ingesting much of the actual plant material, so rinsing the mouth area may be all that you need to do before leaving for the clinic. In certain circumstances, your veterinarian may also recommend giving your dog an appropriate pain reliever or antihistamine. 

If a larger amount of the plant material or sap was ingested a visit to the veterinarian’s office may be needed. Inducing vomiting is not recommended as this can cause additional damage to already injured tissues. IV fluid treatment will be offered to prevent dehydration, and if an antihistamine was not previously dispensed it is likely to be administered as an intramuscular injection at this time. Gastroprotective medications may also be recommended to prevent additional damage to the lining of the stomach. If the airway is substantially swollen, your canine may need to be kept under observation in the veterinarian’s office until the swelling has diminished.

Prognosis for dogs affected by ingesting small amounts of any of the varieties of plant containing the calcium oxalate crystals, such as the Chinese evergreen, is usually quite good. The painful effects of the crystals in the mouth and gastrointestinal tract usually fade within twelve to twenty-four hours from ingestion, although any swelling in the airway should be evaluated by a professional. Massive doses of calcium oxalate crystals are rare due to the preliminary pain and discomfort in the mouth. When larger doses do occur they can cause lifelong liver and kidney damage so more frequent monitoring of the liver and kidneys may be recommended in the event of the ingestion of substantial quantities of the sap.