Veterinary chemicals

Veterinary chemicals are drugs or medicines used to treat or prevent disease, injury and pests in animals.

Without them the welfare of livestock, domestic animals and native fauna would be negatively impacted. Productivity of livestock would also be compromised.

The use of veterinary chemicals in livestock is controlled through the Agricultural and Veterinary Chemicals (Control of Use) Act 1992. Many of these controls relate specifically to livestock in order to ensure that chemicals are used appropriately and do not compromise domestic and international trade.

This legislation requires veterinary chemicals to be used safely and in accordance with good agricultural practice to:

  • safeguard against the development of antibiotic resistance in animals which could jeopardise human health
  • prevent unacceptable residues in livestock products, which may jeopardise market access for Victoria's livestock industry.

See our legislation page for further information.

Over-the-counter veterinary chemicals

Over-the-counter veterinary chemicals can be readily purchased from most veterinary chemical retailers and rural merchandise stores.

Examples include:

  • vaccines
  • worm drenches
  • lice treatments.

By law, farmers treating major species, such as cattle, sheep, pigs or chickens, with an over-the-counter veterinary chemicals must use a product that is registered for the intended purpose or get written authorisation from a vet to use the product contrary to the label directions. They cannot be used in an off label manner on major species unless the farmer follows the written instructions of a vet.

Farmers treating minor species such as goats, alpacas and turkeys may be able to use these products off label, depending upon they way they want to use the chemical. For example farmers must not use over the counter veterinary chemicals:

  • at a higher rate than that stated on the label
  • more frequently than stated on the label
  • contrary to a specific label statement.

When using these chemicals off label farmers must also use a sufficient withholding period (WHP) to ensure there is no risk of unacceptable chemical residues occurring. The WHP specified on the label applies to the on label use pattern and may not be suitable for an off label use pattern.

Farmers are also not permitted to sell treated stock animals before all WHPs have expired unless the purchaser is advised of this in writing. This notification requirement also applies in situations where stock have entered land that that has been treated with an agricultural chemical and the WHP has not expired (where stock have broken through a fence and grazed on a paddock that has been sprayed with an insecticide and the WHP has not expired).

Prescription animal remedy veterinary chemicals

Prescription animal remedy products, such as antibiotics, are legally available only from a vet for animals that are under their care. These products are easily differentiated from over-the-counter products as they contain the phrase 'Prescription Animal Remedy' on the front label of the product.

These products must only be used in strict accordance with the label directions or the written directions of the dispensing vet.

These chemicals must only be used in strict accordance with the label directions or the written instructions of the dispensing vet. These instructions can be provided in two different ways:

  • labels printed by the vet that are attached to each container of the product sold
  • advice notes that are provided by the vet when the product is dispensed or at the time treatment starts.

A prescription animal remedy dispensed for one purpose cannot legally be used for any other purpose without the written permission of the vet. A person that does not comply with this requirement also jeopardises their ability to possess these chemicals in the future, which may have a big impact on their activities.

A vet cannot dispense prescription animal remedy products to treat animals unless the:

  • client is a bona fide client with records to prove this
  • vet has established a therapeutic need
  • vet has responsibility for and current knowledge of the health of the animals and has records that support this.

The Drugs, Poisons and Controlled Substances Act 1981 places complimentary controls over the supply, possession and use of prescription animal remedies. The Veterinary Practitioners Registration Board of Victoria also regulates these same activities through their registration responsibilities.

When treating stock animals with a prescription animal remedy and no ongoing treatment is required, vets should provide the farmer with a written advice note containing the same information that is required on the product label. This enables the farmer to keep the appropriate chemical use records and adhere to relevant WHPs.

Any supplied veterinary chemical product or prescription animal remedy that does not have an APVMA label, or a label supplied by the veterinary practitioner or an advice note should report this issue to Agriculture Victoria on 136 186 or contact

Key pages

Record keeping — Ensure you understand the record-keeping requirements of using veterinary chemicals, plus information on record-keeping requirements for veterinarians. Also access Agriculture Victoria's record-keeping templates to assist you in meeting your record-keeping obligations.

Residue management — General information about preventing unacceptable residues in all agricultural produce, as well as withholding period and export slaughter interval information for vets.

Off-label use of veterinary chemicals — Requirements for legal off-label use of prescription and over the counter veterinary chemical products.

Chemical use legislation — This page provides links to the relevant Acts, regulations, orders and prohibitions associated with veterinary chemical use.

Veterinary practitioner requirements — Information specifically for Vets in regard to labelling, advice notes, withholding periods, record-keeping and 'do not' statements on labels.

Page last updated: 17 Jun 2020