Summary: Substitution is a worldwide problem arising from professional pride and status and pressure of economics. Substitution, legal or otherwise, is encouraged by governments, international agencies, professional and quasi-official bodies. Some faults lie in industry and the developing use of marks but generally it is economic pressures at a time of restricted resources and increasing demand that make for economy in all sections. It is thought that the use of generic names aids economy and that is why restrictions are placed on marks in all parts of the world.