All parts of the plant are regarded as toxic, although the toxic principles within it are unknown. This has caused some to dispute whether the house pine is indeed a threat to pets including cats, however erring on the side of caution is the safest course of action. The needles of the house pine can cause mild skin irritation upon contact, and if eaten or vomited up, can damage internal tissues, causing choking hazards. The house pine is very slow-growing, although it can eventually reach heights over 6 feet. It is sometimes used as a Christmas tree, and in these instances, the water that the tree is kept in may harbor harmful bacteria and cause a cat to become very ill if it is drunk.

The Araucaria heterophylla, or house pine as it is often called, is a small evergreen tree often kept indoors as an ornamental plant. It is a part of the Araucariaceae plant family and goes by the common names of Norfolk pine or Australian pine in addition to being known as a house pine. The tree is called a pine due to its appearance, and is not actually a part of the pine tree family. House pines are native to South America and are tropical plants that can not survive frosts or harsh winters. 

Ingesting portions of the house pine may cause a moderate gastrointestinal response in some cats. External contact may cause itching or inflammation. All signs to watch for are listed as follows:

Chewing or consuming parts of the house pine may lead to a negative reaction from the cat. In very southern climates in the United States, the house pine can grow outdoors, although it is more commonly found potted indoors. Around the holiday season, the plant is sold in many grocery stores around the country, and is likely to be found used as decoration. The house pine is an unusual food choice for a cat, however curious cats or kittens may try to sample the hard needles.

If your cat eats plant material from a house pine and negative symptoms follow, take it into a veterinary clinic for a professional assessment. The cat's medical history may be needed in determining whether previous health conditions are contributing to the current illness. You may be asked about the type of house plants in your home, and if your cat is allowed outdoors.

The veterinarian will perform a complete physical examination of the cat to note all of the symptoms that have developed. A blood sample may be taken at this time for a complete blood count and a biochemical profile to be run. These tests will provide insight on the cat's overall health condition. Urine may also be collected to test for blood or minerals passing through the body. This helps the vet to determine if the cat's liver and kidneys are functioning properly.

If it is determined that treatment is needed, it will likely be symptomatic, as there is no specific procedure to assist a cat who has eaten house pine. Due to the shape and sharpness of pine needles, the pet may also have to be monitored for choking if it is vomiting for a long period of time.

The oral cavity of the cat should be flushed with water to remove all bits of plant material in the mouth. The veterinarian may decide to induce vomiting if there is not a great threat of choking. 

Lengthened periods of vomiting or diarrhea can leave a cat very dehydrated. If this is the case, intravenous fluid administration may be needed to balance volumes inside the cat and stabilize its condition.

This may be given to the cat to help absorb any toxins in the digestive system and allow them to safely pass through the intestines without being digested.

House pine poisoning is not commonly reported and fatalities from ingestion of house pine is unheard of. This does not mean that no threat exists, however, the likelihood of your cat becoming ill from eating house pine is very low. A full recovery is expected after the initial illness has passed.

There may be a real threat to a cat's health in the water that house pine Christmas trees are kept in. This water can become full of harmful bacteria and lead to internal infections if the cat drinks it. If you have a house pine in your home, do all you can to prevent your cat from accessing it. Some may choose not to keep the plant in their home as an extra precaution.