What is eyebright?
Eyebright, from the Euphrasia officinalis plant, is an herbal supplement used as an antimicrobial (antiseptic), anti-inflammatory, and astringent, most commonly in dogs, cats, and horses. Eyebright contains substances such as tannins, aucubin, and quercetin that are likely the active ingredients.
It is typically used to supplement treatment for eye conditions such as conjunctivitis (inflammation of the tissues around the eyeball), allergies, or corneal ulcers. One common application is to treat conjunctivitis in cats caused by upper respiratory viruses.
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 is eyebright given?
- Eyebright comes as a capsule, powder, or liquid tincture. It may be compounded into eye drop form.
- Topical drops are given directly into the eye. All other forms are given orally (by mouth).
- Oral forms may be given with or without food.
- Measure liquid forms carefully.
- Ensure you are using the correct formulation for the route of administration.
- Follow your veterinarian’s instructions on administering this medication carefully and give it for the entire time prescribed by your veterinarian, even if your pet is feeling better.
This medication should take effect within a few hours.
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?
Eyebright may cause the following side effects:
- Mild redness or irritation if using topical eye drops
Serious adverse reactions may occur. If any of the following signs develop, stop giving eyebright 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 effects may last longer in pets with liver and/or kidney disease.
Are there any risk factors for this supplement?
DO NOT USE eyebright in:
- Pets that are allergic to any component
USE WITH CAUTION in:
- Pets that are pregnant or lactating
- Pets that have had eye surgery
- Pets with diabetes
Are there any drug interactions I should be aware of?
The following medications should be used with caution when given with eyebright:
- Insulin
Vitamins, herbal therapies, and supplements have the potential to interact with each other, as well as with prescription and over-the-counter medications. Be sure to tell your veterinarian about any medications (including all 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 eyebright?
- Store the medication in a cool, dry location.
- Protect from light.
- Follow manufacturer’s specific storage instructions.
- Keep medication 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.
