What is English Holly Poisoning?
When eaten, the leaves, berries, bark, and seeds are all mildly toxic to most mammals. English holly contains multiple toxins including saponins, methylxanthines, cyanogenic glycosides and theobromine alkaloids. A cat's liver has a difficult time digesting plant glycosides, as once the sugar portion of the molecule is stripped away, the chemical becomes harmful to the body. Theobromine alkaloids are very similar to caffeine and cause an over-stimulation to the central nervous system. The spines of the leaves can also cut the oral tissues when chewed. Poisoning by English holly is generally not fatal, and the plant has even been used medicinally by humans or as a tea for its caffeine-like effects.
English holly, also known as European holly or winterberry, is an evergreen plant that commonly grows as a shrub, tree or climbing plant. It is well known for its shiny, spined leaves and bright red berries, and it is often used as a holiday decoration because of these characteristics. English holly can also be found growing in many gardens throughout the United States, although it is not a native plant. The Latin name for English holly is Ilex aquifolium and it is a part of the Aquifoliaceae family of plants.
Symptoms of English Holly Poisoning in Cats
Depending on how much plant material has been consumed, symptom severity will usually be mild to moderate. Gastrointestinal upset is the most common response after English Holly has been eaten. All signs to watch for include:
- Excessive drooling
- Smacking of the lips
- Head shaking
- Abdominal pain
- Loss of appetite
- Quickened pulse
- Low blood pressure
Causes of English Holly Poisoning in Cats
English holly is a very common seasonal decoration used at Christmas time. Because of this, indoor cats may be just as much at risk of exposure to the plant as outdoor cats. English holly can be found growing in gardens year round. Most cats are deterred from eating the foliage due to the very bitter taste of the leaves.
Diagnosis of English Holly Poisoning in Cats
If you suspect your cat has been poisoned from eating English holly, bring it in to be professionally assessed by your veterinarian. You may be asked to provide the cat's medical history to help rule out possible causes of digestive distress if symptoms have begun but you did not witness the cat eating any plants. If you did see the cat eating a plant but are unsure of what it was, bring a small clipping with you so that the vet may identify it. If it is near Christmas time, your vet may ask if you have brought holly into the home. You may also be asked if you allow your cat outdoors or not.
The veterinarian will then perform a complete physical examination of the cat, checking for all symptoms of illness. A stethoscope may be used to listen to the heart and lungs. The vet may find a rapid heartbeat paired with a lowered blood pressure. Blood will be taken for certain tests to be run, including a complete blood count and a biochemical profile. This will give a more complete picture of the cat's overall health. Urinalysis may also be needed to assess how the organs are functioning within the body.
Treatment of English Holly Poisoning in Cats
The amount of treatment needed will vary based on the severity of the symptoms and the amount of plant material that has been consumed. Hospitalization may be required in extreme circumstances.
Rinse the Mouth
The oral cavity should be flushed with water to remove all remaining plant material, including any potentially painful bits of spiny leaves.
Remove Stomach Contents
The cat will be made to vomit using hydrogen peroxide. If this can not be done, a gastric lavage (stomach pump) will be performed instead to remove all remaining plant material from the stomach.
This may be given to the cat to help absorb all toxins in the digestive tract and trap them so that they can safely pass through the body and be expelled as waste.
If the cat has become dehydrated from excessive vomiting or diarrhea, intravenous fluids may be administered to rehydrate the animal.
Recovery of English Holly Poisoning in Cats
Cats who have been poisoned by English holly tend to make a full recovery after the toxins have passed through the body. No lasting health problems should exist after the illness. There are no recorded cat fatalities from English holly poisoning. Keeping your cat indoors can help prevent it from coming into contact with English holly growing in people's gardens.
If you use English holly as a Christmas decoration, remove all of the berries prior to bringing the branches into your home. The berries dry out when indoors and often fall to the ground where they are very accessible to pets. Using synthetic holly is another option to make your home look festive while keeping your cats safe.