The chemoinformatics toolkit CACTVS , has capabilities of reading and writing Substance Indexing SPL files for small molecule drugs. Capabilities to write and read Reaction SPL files are being implemented, as is an extension of the reaction object to store and process the full range of information which can be expressed in Reaction SPL. The current reaction object is limited to multi-step reaction data as found in MDL RXN/RDF, Reaction SMILES and similar formats. This simple data model will involve significant enhancements.