e-EROS utilizes the full potential benefits of the web by allowing chemical structure, substructure and reaction searching straight from a chemist's desktop. It contains a database of initially 48'000 reactions and around 3500 of the most frequently consulted reagents and is fully searchable by structure and substructure, reagent, reaction type, experimental conditions etc. and allows sophisticated full text searches. Each entry highlights the various uses and characteristics of each reagent, with illustrative examples of its use and is preceded by valuable information concerning physical data, solubility, form supplied in, purification, and where relevant, preparative methods and with literature references to key review articles and seminal papers.