The foliage, stems, and flowers of the Mauna Loa peace lily contain insoluble calcium oxalates; a toxin that affects most mammals, including cats. These calcium oxalates are crystals stored in bundles called raphides. Once the plant material is chewed, the crystals are released and embed themselves in the oral and esophageal tissue of the animal eating them. This serves as a defense mechanism for the plant, as the crystals penetrating the oral cavity cause pain and inflammation. Most poisonous reactions are moderate, however if swelling of the throat begins to occur, breathing can be severely hindered. It should be noted that a Mauna Loa peace lily is not a true lily, and does not contain the same toxins found in lilies that lead to kidney failure.

The Mauna Loa peace lily is a large spathiphyllum hybrid that is a part of the Araceae family. It can be referred to as a “Mauna Loa plant”, or simply just a  peace lily. The plant is native to South America and has a very tropical appearance. The Mauna Loa Peace Lily is an evergreen perennial that can grow up to three feet in height. It has large, glossy leaves that are dark green in color. Large, white flower-like leaves grow around a thick, yellow spadix (a spike of very close flowers). These blooms last for a very long time. The plant is often kept potted, as it does not tolerate the frost and often needs to be indoors. 

Most cases of Mauna Loa peace lily ingestion by cats produce only mild to moderate reactions. Symptom onset is often immediate but can take up to two hours to fully manifest. All signs to watch for include:

Peace lilies are often used as indoor plants as they are easy to keep and unique to look at. Some people may chose to keep the plant outdoors on the patio in the summer months. Both indoor and outdoor cats may be exposed to Mauna Loa peace lilies. Severe poisonings are rare due to the fact that eating the plant causes a painful irritation of the mouth, deterring most cats from eating more than a bite.

The easiest way to identify a Mauna Loa peace lily poisoning is by witnessing your cat eating the plant or by noticing bite marks or other obvious damage on your lily. If neither of these occurrences have taken place, the diagnostic process may be a bit more complicated. You will need to provide your veterinarian with the cat's full medical history to help differentiate a poisoning from pre-existing health problems. You may also be asked about what kind of house plants you keep and if you allow your cat outdoors.

The veterinarian will then perform a complete physical examination of the cat, noting all symptoms that have developed. In severe cases of poisoning, treatment to stabilize the cat may be started before a diagnosis has been made. A sample of the cat's blood will be needed to run a complete blood count and a biochemical profile, which will help reveal if the cat has very low electrolyte levels. This suggests that the cat has become dehydrated. Urinalysis may also be useful in measuring how well the liver and kidneys are functioning. Calcium oxalate crystals can wreak havoc on these organs. 

There is no specific course of treatment to handle a Mauna Loa peace lily poisoning. Symptoms will be addressed and treated as they arise. The cat's vital functions should be stabilized as soon as possible. 

Wash Oral Cavity 

Flushing the mouth and surrounding areas with water can help relieve irritation caused by calcium oxalate crystal penetration. Any part of the cat that has touched the plant may also need to be washed. 

Medication 

Certain medications can be given to the cat to help ease symptoms. Antihistamines such as diphenhydramine can be administered to open blocked airways. Kapectolin may be used to coat the stomach lining and prevent internal irritation.

If the cat has become dehydrated from excessive illness, rehydration using intravenous fluids may be necessary. Electrolytes can also be given to increase levels in the body.

The period of illness following the consumption of Mauna Loa peace lily generally lasts from 12 to 24 hours, with mild symptoms remaining up to two weeks. The majority of cats make a full recovery with no lasting effects. This is mainly because most cats do not eat large portions of the plant. The severity of the poisoning will be directly related to how much plant material has been ingested. If your cat develops breathing difficulties during the episode, it will need to be closely monitored throughout the poisoning.

While many people keep this plant in their home, extra precaution must be taken to ensure it is kept out of the reach of any house cats. Some have chosen to remove the plant for their cat’s safety. Keeping your cat indoors will help prevent it from coming into contact with a Mauna Loa peace lily outdoors during the summer months.