Arsenic Trioxide database (ATOdb) is a comprehensive, user-friendly online one-stop platform to provide experimentally supported information for ATO, including its condition, target genes and drug combination, which was gotten from manually reviewing 3,479 published papers. The current version of ATOdb contains 8,373 entries for ATO condition, 5,927 entries for ATO related genes with direct experimental evidences, and 2,019 entries for drugs which have combined potentiating effect on ATO, as well as 423 entries for drugs with combined detoxification effect. Three different query options were provided based on ATO affected condition, drug combination, and target of ATO. Furthermore, ATOdb provides a tree structure and a human body map to browse the data and a link is provided for users to download data from ATOdb. ATOdb can be widely used by medicinal chemists, pharmacists, physicians, students and the general publics. The application of ATOdb would accelerate the investigation of ATO from the benchside to the bedside, as well as the rational use of ATO and Individualized treatment.