Black and Green Tea

What are black and green teas?

Black and green teas are made from the leaves and buds of the tea plant, Camellia sinensis. Black tea is made from green tea leaves that have oxidized. This oxidation process results in decreased levels of catechins, the active ingredient in tea, so green tea has higher levels of catechins than black tea.

Catechins are a type of polyphenol that have been shown to possess strong antioxidant properties, preventing damage to DNA and reducing risk of cancer cell formation. Through their antioxidant activity, the catechins in green tea may also profoundly reduce inflammation of the liver and gastrointestinal tract, providing a potential benefit to small animals with enteritis and hepatitis. 

Black tea also contains theaflavins and thearubigins, which inhibit carcinogens and protect against oxidative damage. In humans, black tea is used as an anti-cancer agent and to lower blood cholesterol.

The U.S. Food and Drug Administration (FDA) does not review non-drug health products (e.g., herbals, nutraceuticals, shampoos, and other supplements) for safety or effectiveness before they are sold to the public. Manufacturers of non-drug health products must ensure their products are safe and labeled accurately. 

The FDA requires that these non-pharmaceuticals contain a disclaimer that says, “This product is not intended to diagnose, treat, cure or prevent any disease.” Health Canada licenses “veterinary health products” after reviewing safety, efficacy, and manufacturing information provided by the manufacturer. These products are not tested by Health Canada.

Your veterinarian is the best source of information about the safety of non-drug health products in pets. Just because a product is natural does not mean it is safe. All medicines and medicinal plants are potentially toxic if used inappropriately or given at high doses. Supplements can also have side effects, like pharmaceuticals. Few supplements and herbs have been subjected to rigorous scientific trials to determine their efficacy.

Although the information in this handout may be helpful, it also may be incomplete and may not represent the full range of effects the supplement could have on your pet.

How are black or green teas given?

• Black and green teas come in powder or leaf forms that are often steeped into a liquid.
• All forms are given orally (by mouth).
• May be given with or without food.
• Follow your veterinarian’s instructions on administering this medication carefully and give for the entire time prescribed by your veterinarian, even if your pet is feeling better.

This supplement should take effect within a few hours, although outward effects may not be noticeable.

What if I miss giving my pet the supplement?

If you miss a dose, give it as soon as you remember. However, if it is almost time for the next scheduled dose, skip the missed dose and resume the regular dosing schedule. Do not give the pet two doses at once..

Are there any potential side effects?

Black and green teas may cause the following side effects:

• Nervousness, sleeplessness, increased heart rate, and anxiety (if using caffeinated tea)

Serious adverse reactions may occur. If any of the following signs develop, stop giving black and green teas and contact your veterinarian immediately:

• An allergic reaction such as irregular breathing, rash, fever, puffiness and swelling around the face

Drug sensitivities can develop over time with repeated exposure. Your pet may have no reaction after the first few doses, but may develop a sensitivity later. It is important to watch for signs of an allergic reaction over the entire course of treatment.

Other side effects may occur. If you notice anything unusual, contact your veterinarian immediately. This short-acting medication should stop working within 24 hours, though adverse effects may last longer if caffeinated versions are administered.

Are there any risk factors for this supplement?

DO NOT USE black or green teas in:

• Pets who are allergic to any component of the teas

USE WITH CAUTION in:

• Pets with kidney disease
• Pets with stomach or intestinal ulcers,
• Pets with heart disease, high blood pressure
• Pets with glaucoma

Are there any drug interactions I should be aware of?

The following medications should be used with caution when given with black and green teas:

• Antifungals
• Fluoroquinolone antibiotics
• Insulins
• Monoamine oxidases inhibitors (MAOIs)
• Phenylpropanolamine
• Theophylline
• Warfarin

Certain medications may interact with black and green teas, so it is important to tell your veterinarian about any medications (including vitamins, supplements, or herbal therapies) that your pet is taking before starting any new treatment.

Is any monitoring needed with this supplement?

• Your veterinarian will let you know when and how they want to reassess your pet to ensure the supplement is working and not causing side effects.
• At home, monitor for any abnormal changes. If any occur, discontinue the medication and contact your veterinarian.

How do I store green/black tea?

• Store the medication in an airtight container, either at room temperature or in the refrigerator, according to manufacturer’s directions.
• Protect from light.
• Keep the container out of reach of children and pets.

What should I do in case of emergency?

If you suspect an overdose or an adverse reaction to the medication, call your veterinary office immediately. If they are not available, follow their directions in contacting an emergency facility. Be prepared to provide information about the product and your pet's weight and symptoms. Report any adverse effects to the FDA or Health Canada.