It is the bulbs of the hyacinth that present a threat to cats, as they contain heightened concentrations of toxins. These toxins include allergenic lactones, lycorine alkaloids, and calcium oxalate raphides. The allergenic properties often produce internal or external irritation. The calcium oxalate raphides contain many sharp crystals that, once released, embed themselves in the oral and esophageal tissues of the cat, causing pain and inflammation. These bulbs are light in color and can indeed cause death in cats if consumed. 

Hyacinths are common bulbed plants that grow all over North America. Scientifically they are known as “Hyacinthus orientalis” and are a part of the Liliaceae plant family. Hyacinths are very popular due to their clusters of vividly colored blooms that appear in the early spring. These flowers grow on stalks in clusters and come in blues, purples, pinks, yellows and whites. The shape of the flower is often trumpet or bell-like, and they are very fragrant. The leaves are fleshy in appearance and often narrow shaped.

Consuming hyacinth bulbs causes a mild to moderate response in most cats. Severe cases do happen if a large portion of the bulb has been consumed. Skin irritation may also be noted if the cat has touched the plant. All signs to watch for include:

Hyacinths are loved by many gardeners and because of this can be often found growing in neighborhoods. The plant is also often sold in a pot to be kept indoors. This means that both indoor and outdoor cats may be exposed to hyacinths at some point in their lives. As it is the bulbs that contain the most toxins, cats who dig up plants have a much higher risk of potentially consuming the toxic portions of the plant. This behavior is not common in cats, but it is not unheard of. Most cats do not eat much of the plant, as it causes pain and irritation of the mouth when chewed.

Take your cat in for a professional assessment if you are concerned about its wellbeing, or if severe symptoms involving breathing and heart rate have begun to develop. Treatment may begin before a diagnosis has been made if the cat's vital functions need to be stabilized. If you witnessed your cat eating plant material but are unsure of what it was, bring a small clipping with you for the veterinarian to identify. Providing your cat's full medical history can also assist in getting it appropriate care.

A complete physical examination of the cat will be performed to note all symptoms that have manifested. Routine tests will be run using samples of your cat's blood. These tests generally include a complete blood count and a biochemical profile. Urine samples may also be assessed to see if the kidneys or liver have been damaged, as is often the case with calcium oxalate poisoning. The vet may listen to the cat's heartbeat and breathing and may discover abnormalities in severe cases.

Immediate treatment of Hyacinth poisoning may lead to the best outcomes. Treatment is symptomatic and focuses on stabilizing the cat and supporting it throughout the illness.

This may involve washing out the cat's mouth to remove all remaining bits of plant material and soothe irritation of the oral cavity. The vet may induce your cat to vomit by giving it hydrogen peroxide. A gastric lavage may also be performed to remove all contents of the stomach.

This may be administered to help absorb all toxins in the stomach and trap them so that they may pass through the body undigested.

Depending on the cat's condition, supportive care may include monitoring the heart and breathing of the cat during the episode. Certain medications can be used to help normalize the cat's heartbeat. If the cat has become dehydrated, intravenous fluids may also be given. The cat will need to be hospitalized during this time.

If a large portion of the hyacinth bulb has been consumed by a cat, the result can be fatal. Poisonings from hyacinth plants are rare but do happen. Kittens are the most at risk due to their small body size and heightened curiosity levels. Keep this plant far out of your cat's reach. It may be best not to allow your cat outdoors to prevent it from consuming toxic plants such as the hyacinth.