This content applies to both human and veterinary medicines
'One substance – one assessment' (OSOA) refers to a legislative framework of the European Union (EU) designed to enable more coordinated, efficient and transparent chemical safety assessments.
Its overarching aim is to protect people living in the EU and their environment, while recognising the essential role chemicals play in everyday life.
The framework aims to:
OSOA applies to a wide range of products regulated at EU level, including biocides, pesticides, food and toys.
The legislative framework entered into force on 1 January 2026.
For more information on EMA's partners and networks, see:
A central element of the OSOA framework is establishing a new common data platform on chemicals used in the EU under Regulation (EU) 2025/2455.
The aim is to support close cooperation and systematic data sharing between EU bodies involved in chemical safety assessments.
The European Chemicals Agency (ECHA) will manage this data platform with support from EMA and three other EU agencies involved in chemical safety assessments. These are the European Food Safety Authority (EFSA), the European Environment Agency (EEA), and the European Agency for Safety and Health at Work (EU-OSHA).
The data platform is expected to be operational in 2029.
EMA will contribute data to the common data platform established under the OSOA legislative framework.
To ECHA, EMA will submit safety data on chemicals that are active substances of certain medicines defined in the framework. These data include:
To EEA, EMA will provide available data on 'early warning signals' from its medicine evaluation activities.