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Guidance

Substances recognised as medicinal by function in veterinary medicines

List of substances recognised as medicinal by function.

This is part of a guidance collection and should be read in association with Advertising non-medicinal veterinary products.

The following is a list of substances recognised as medicinal by function. Some have established limits below which they are considered non-medicinal.

The notes section in this list is currently under review. We expect to publish the updated version by the end of October 2026

Any product applied to an animal that contains a substance on this list is considered medicinal by function unless that substance is below any stated limit.

Unless otherwise stated in this list, any product containing an active substance present in an authorised veterinary medicine as presented on the VMD’s Product Information Database is considered medicinal by function.

This list is not exhaustive.

Substance Notes
Acetylcysteine / N-Acetylcysteine Medicinal at any level
Adelmidrol Medicinal at any level
Adenosylmethionine (aka SAMe) Medicinal in any product presented for effects on liver or joint health
Belladonna Medicinal at any level
Benzoyl Peroxide Medicinal in a product presented to treat bacterial skin infections at a concentration exceeding 2.5%
Bismuth Sub Carbonate Medicinal when orally administered
Bronopol Medicinal but permitted as a preservative in leave-on and rinse-off topical products at concentrations not exceeding 0.1%
Boric Acid Medicinal when included at levels exceeding Talc - 5% Oral hygiene – 0.5% All other products – 3% Products containing this substance require the warning “Do not use on damaged skin”
Cannabidiol (CBD) Medicinal at any level
Cannabigerol (CBG) Medicinal. Metabolises into CBD
Capsaicin Medicinal by function when applied topically at concentrations exceeding 0.012% due to analgesic effects
Chlorhexidine Gluconate Medicinal when applied to intact skin at concentrations exceeding 4%, or when included in first aid products at concentrations exceeding 0.3%
Colostrum Medicinal when treated to ensure the colostrum will contain specific antibodies. A colostrum or colostrum-based product containing pure colostrum is not medicinal, provided that no reference is made to disease, immunoglobulin content, antibodies, IgA, IgG, or the immune system
Diflubenzuron Medicinal at any level
Foxglove (Digitalis) Medicinal at any level
Guanidinopropionic Acid Medicinal at any level
Iodoform Medicinal at concentrations exceeding 10%
Palmitoylethanolamide (PEA) Micronised and Ultra-Micronised PEA is medicinal. Has anti-inflammatory and antinociceptive properties. A synthesised alternative to CBD. Unmicronised is not considered medicinal but products containing unmicronised PEA must be declared as such. This declaration must be readily apparent on the packaging and wherever a reference to PEA is made
Potassium Iodide Medicinal at concentrations exceeding 1% for oral use
Sodium bicarbonate Except in feeds exclusively for ruminants. Inclusion in orally administered products in concentrations greater than 1% is considered medicinal due to its recognised antacid activity
Thymol Medicinal by function at any level

Updates to this page

Published 14 January 2026
Last updated 25 September 2026 Show all updates
  1. Reviewed and updated with the removal of some substances. The notes section of the list is subject to further review.

  2. First published.

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