A significant number of Active Pharmaceutical Ingredients (APIs) have been identified in the environment and in surface waters. Data on the environmental hazards associated with these substances are emerging but are still scarce. We have compiled publicly available ecotoxicity data for APIs into a database called WikiPharma. The use of the database is free of charge. It can be accessed and updated continuously as a "wiki". The aim of WikiPharma is to provide an easily accessible, comprehensive and up-to-date overview of effects caused by pharmaceuticals on non-target organisms. The database currently contains basic information, i.e. substance name, ATC code(s) and pharmaceutical group(s), for 831 APIs representing 35 different drug classes. Effect data have been identified and included for 116 of these substances. These ecotoxicity test data have been extracted from 156 different sources. The development of a comprehensive database on ecological hazard of APIs can facilitate identification of data gaps and promote environmental risk assessment of these substances. The database is available at www.wikipharma.org.