Calla lilies are elegant, pretty flowers that are often found in wedding bouquets, artwork, flower arrangements or in magazine shoots. They come in a variety of colors, ranging from pure white to almost black, with nearly every color in between, including red, pink and yellow. As common as they are, as with any plant, calla lilies may pose a health risk to families and pets alike.
The calla lily blooms throughout the summer. In Northern states, this plant can be treated as an annual, but in Southern states with warmer winters, this plant can be used as a perennial. Calla lilies are native to Africa and, according to Jennifer Schultz Nelson of the University of Illinois, "are not true lilies."
Calla lilies are extremely toxic to humans of any age, though children may be more susceptible to extreme illness or death. Every part of the calla lily — from the top of the flower to the tip of the roots — is poisonous, with the roots being the most poisonous portion. When consumed, it can cause burning of the mouth and throat, swelling of the oral cavity, swelling or pain in the eyes, redness, vomiting, nausea or diarrhea. According to Melissa Kniceley of George Mason University, as little as 5 g of oxalic acid can be fatal.
Calla lilies produce an oxalic acid. When ingested, it mixes with the acid in the stomach and saliva in the mouth to produce various symptoms. After it enters the bloodstream, oxalic acid binds together with any calcium that is present in the blood. This creates calcium oxalate, which is insoluble and cannot be released from the body, resulting in toxicity and causing damage to the kidneys, nerves, brain, heart, eyes, skin and mucous membranes, such as those found in the oral cavity.
Unfortunately, calla lilies are also extremely toxic to pets, namely cats and dogs. According to the ASPCA, the same calcium oxalates that form in a human’s blood will also affect a pet in the same way. Pets who consume calla lilies may suffer from oral irritation, excessive drooling, vomiting and difficulty with swallowing. Just as with humans, if enough of the plant is consumed, the pet may suffer from death.