Calla lilies are popular ornamental plants prized for their elegant, trumpet-shaped flowers and lush foliage. Despite their beauty, all parts of the calla lily plant are toxic to both humans and common household pets like dogs and cats. Ingestion or chewing on the plant material causes significant discomfort and irritation, though it is rarely life-threatening. The danger primarily stems from an immediate, intense burning sensation and localized swelling in the mouth and throat. Understanding the toxic mechanism and resulting symptoms is important for safely managing these plants.
The Mechanism of Toxicity
The toxicity of the calla lily is due to insoluble calcium oxalate crystals, which serve as the plant’s primary defense mechanism. These microscopic, needle-like structures, known as raphides, are stored under pressure within specialized cells throughout the plant. When the plant tissue is chewed, these cells rupture and forcibly eject the sharp crystals into the surrounding tissue. This physical penetration causes immediate, intense pain and localized irritation of the mucous membranes in the mouth and throat. Because the crystals do not dissolve in water, they continue to irritate the tissues until they are physically removed.
Recognizing Symptoms in Humans and Pets
Symptoms of calla lily exposure begin immediately upon contact due to the rapid release of irritating crystals. In humans, the initial sign is intense, burning pain in the lips, mouth, tongue, and throat. This irritation quickly causes swelling, increased saliva production (drooling), and difficulty swallowing or speaking. If the plant sap contacts the eyes, symptoms include immediate burning, redness, and tearing.
For pets, signs are often expressed through distress behaviors focused on the mouth. Dogs and cats commonly exhibit excessive drooling, pawing at the face, and vocalizing due to oral pain. Vomiting and refusal to eat are also common as irritation extends into the gastrointestinal tract. Although rare, severe throat swelling in both humans and animals can lead to difficulty breathing, which is the most significant danger.
Immediate Response and Safety Measures
If exposure is suspected, the first action is to ensure the airway is clear and stable. For humans, gently wipe the mouth with a cool, wet cloth to remove plant material and rinse the lips with water. Offering something cold and creamy, such as milk or yogurt, can provide relief by coating the irritated tissues. Do not give anything to eat or drink if the person is struggling to swallow or breathe.
For pets, rinse the mouth area if the animal allows it, and contact a veterinarian or a specialized Pet Poison Helpline immediately. For human exposure, contact the national Poison Help hotline (1-800-222-1222) or seek emergency medical attention, especially if breathing is affected. Preventative safety measures include placing calla lilies out of reach of children and pets.