Although cinnamon is technically classified as non-toxic to cats, it can become toxic at certain levels-- especially if your cat is exposed to the higher concentrations typically found in essential oils. Cats can be particularly susceptible to toxicity from cinnamon for a couple of reasons. Cats lack some of the liver enzymes that break down cinnamon compounds which can then build up if your pet is exposed to a high concentration in a short period of time, or, if your pet is exposed to a lower concentration over a long period of time. Also, because cats have thin skin, which can easily absorb cinnamon compounds applied in essential oils. This puts them at an increased risk for cinnamon toxicity.

Cinnamon can also act an irritant on the skin or in the oral cavity, causing rash and allergic-type reactions in cats and other animals. Because cats have sensitive skin and a keener senses of smell than humans, they are at an increased risk of reaction from exposure to cinnamon or the cinnamon aroma. If your cat exhibits symptoms of cinnamon allergic reaction or toxicity after being exposed to cinnamon you should consult with your veterinarian immediately.

Cinnamon, also referred to as cinnamomum, is commonly found in households and human food. There are two types of cinnamon: cassia and ceylon. Cassia cinnamon is commonly used in North America and contains higher levels of a substance called coumarin then ceylon cinnamon. Coumarin in high concentrations is used as a rodenticide (rat poison) and causes liver failure and haemorrhaging in rodents. In humans, cinnamon is sometimes used as a natural medicine to treat diabetes as it lowers blood sugar, or as a blood thinner.

A variety of symptoms can result from an allergic or toxic reaction to cinnamon and its organic compounds. Symptoms vary by level and mode of exposure.

Allergic reaction from exposure to the skin or oral cavity:

Respiratory reaction to inhalation:

Symptoms of cinnamon toxicity from ingestion or absorption of cinnamon compounds:

Cinnamon toxicity is unlikely to occur under normal, household use of powdered cinnamon. It would take a large amount of powder, or the inhalation of the powder to cause a reaction. However, as essential oil use is becoming more common in households, there is an increased risk to cats from exposure to cinnamon essential oil, which has a much higher concentration of the compounds that can be harmful to cats.

Cats can accidentally be exposed to toxic amount of cinnamon in the following ways:

Intentional exposure can occur because:

It is important to understand that:

Diagnosis of cinnamon toxicity or allergic reaction will depend heavily on the pet owner’s ability to describe any exposure to cinnamon their pet may have experienced. Your veterinarian will perform a complete physical examination and ask about your cat’s medical history to rule out any other causes for your pet’s symptoms. If symptoms of organ failure are occurring, your veterinarian may perform tests including blood and urinalysis tests to assess organ functioning. 

Treatment will depend on the extent of illness and symptoms resulting from your pet’s reaction to cinnamon.

For allergic reactions, the affected area should be washed with water and mild detergent. If irritation of the eyes occurred, the eyes should be well irrigated to remove the irritating substance. Steroids have been found to worsen rash from cinnamon exposure in other animals and will probably be avoided in your pet. 

If toxicity has occurred, prognosis will depend on the amount of damage that has occurred to your pet’s organ systems. Treatment usually consists of supportive care until the toxin passes out of your cat's system and treatment to relieve any symptoms being experienced by your pet. If organ damage has occurred, the prognosis is guarded and your vet will provide any therapeutic care that is available and appropriate to restore organ function. Vitamin K is used as an antidote for coumarin poisoning in pets exposed to high doses of this substance which is also found in cinnamon. Vitamin K therapy may be useful if symptoms of coumarin poisoning (hemorrhaging from blood thinning) are occurring. 

If you pet is in respiratory distress due to inhalation or ingestion of cinnamon, airway management and oxygen therapy will be used as appropriate.

Your pet’s recovery depends on the extent of exposure and any organ damage that has occurred. Allergic reactions usually clear up in a short period of time and removal of any cinnamon exposure from your cat’s environment should resolve the problem. Home treatment of cats with essential oils should be avoided; consult your veterinarian before attempting any treatments for your pet’s health conditions. Recovery from toxicity will require rest and any medications and diet prescribed by your veterinarian to recover organ function and relieve symptoms.