It is not intended in this paper to review all the requirements for registration or licensing of medicines, because they are well documented elsewhere and laid down in directives by government agencies, in different countries. Equally, the purpose is not to detail every step that has to be taken by a medicinal product on the long and hazardous path from discovery to marketing, but a sketch map of the route will be drawn, with emphasis on some particular obstacles and dangers that may be encountered on the way. Because a product is only for use in animals, this does net necessarily make the trip any easier. Some of the situations quoted refer to what happens in the United Kingdom, but many can equally apply in Europe and in North America as well as in other parts of the world, like Australia and Japan. Generally, the terms 'veterinary medicine' and 'animal health product' can be considered synonymous and do not refer to a legal or ethical sale and supply status, such as veterinary indicating prescription only, and animal health as on general sale to farmers, including intensive pig and poultry keepers.