Testing of chemicals

Mutual Acceptance of Data (MAD)


The testing of chemicals is labour-intensive and expensive. Often the same chemicals are being tested and assessed in several countries. The OECD Council therefore adopted a Council Decision* in 1981 – on Mutual Acceptance of Data (MAD) - stating that test data generated in any member country in accordance with OECD Test Guidelines and Principles of Good Laboratory Practice (GLP) shall be accepted in other member countries for assessment purposes and other uses relating to the protection of human health and the environment.


A further Council Act was adopted in 1989 to provide assurance that the data are indeed developed in compliance with the Principles of GLP.  This Council Decision-Recommendation on Compliance with GLP establishes procedures for monitoring GLP compliance through government inspections and study audits as well as a framework for international liaison among monitoring and data-receiving authorities. 


A 1997 Council Decision on the Adherence of Non-Member countries to the Council Acts related to the Mutual Acceptance of Data in the Assessment of Chemicals sets out a step-wise procedure for non-OECD countries to take part as full members in this system.


*There are two types of Council Act. A Council Decision, which is legally binding on OECD Member countries, and a Council Recommendation, which is a strong expression of political will.