The prescription is the decisive and critical step before using medicinal products. The prescription follows the examination of the animal(s), the evaluation of the conditions under they live, and the diagnosis made. Prescriptions can only be made by the person under whose care the animals are.

Incorrect prescriptions go hand in hand with misuse and overuse of medicinal products, can endanger the health and welfare of animals and can enhance the occurrence and spread of resistance against antimicrobials and antiparasitic medicines. The quality of the prescription heavily relies upon the training, education and professional ethics of the prescriber. For this reason, the prescriber shall be sufficiently educated, and be licensed by and accountable to the national regulatory or statutory body.