SemanticBits is pleased to announce the availability of Version 2.5 of the Cancer Adverse Event Reporting System (caAERS). The system is freely available at https://wiki.nci.nih.gov/x/OgA5Aw. caAERS is an open source software tool that is used to record and report adverse events that occur during clinical trials. This tool supports regulatory and protocol compliance for adverse event reporting and allows local collection, management, and querying of adverse event data. caAERS also supports service-based integration of data from other clinical trials management systems. caAERS development is funded by National Cancer Institute Center for Bioinformatics and Information Technology (NCI-CBIIT).