GMP is a term that was introduced in 1962 by the US Food and Drug Administration (FDA). The term is synonymous for a collection of behaviour measurements and instructions that have to be taken into consideration during the production and handling of certain products (e.g. pharmaceuticals, food products, cosmetic products and veterinary medicines etc.) with the main goal being that these products are reproducible and reliable in the desired quality.

In the European guide for pharmaceutical products, III/2244/87, Rev. 3, Jan. 1989, valid since 1992 Good Manufacturing Practice, GMP, is defined as:

"that part of Quality Assurance which ensures that products are consistently produced and controlled to the quality standards appropriate to their intended use and as required by the Marketing Authorisation or product specification."

1.	There is not one GMP rule but rather numerous GMP rules plus additional and supplementary guidelines and literature. Whether, or which, GMP rule applies depends on:
	the type of product (final pharmaceutical substance, active or inactive pharmaceutical ingredient, food product etc.) form of administration (oral, parenteral,…) product specification (sterile, low germ content, non-sterile,…) the development stage (development or production) the process step (critical, non-critical) the country of distribution (Europe, USA, Japan)
Only if all these questions are answered is one able to choose the correct GMP guidelines.
2.	GMP guidelines say what has to be done or complied with, but not how.

One of the most frequent requirements of GMP is that something should be designed, constructed and erected in such a way that any kind of cross-contamination with other products is avoided under all circumstances. How this aim is achieved depends on the experience of the individual project leader.

In conclusion: GMP guidelines must be chosen, interpreted and implemented with the necessary experience on a case-by-case basis.