Compounding of drugs from unapproved (bulk) substances for use in non-food animals is medically necessary in certain situations and should be allowed through enforcement discretion, if such compounded products are used under the conditions for extra-label use of approved drugs delineated in the regulations written to implement AMDUCA. Such compounding should be allowed only if effective regulatory mechanisms are in place and implemented to assure that such compounding is patient specific and is performed only in the context of a veterinarian-client-patient relationship.