Stefanie Krens, from Radboud University Medical Center, Nijmegen, The Netherlands, discusses the collaborative tool from her institute and the University of Liverpool; the Cancer Drug Interactions website (https://cancer-druginteractions.org/), which is also available as an app. Cancer drug interactions can be complex, but understanding and avoiding adverse combinations is essential. This interview took place at the International Society of Oncology Pharmacy Practitioners (ISOPP) Symposium 2019, hosted by the British Oncology Pharmacy Association (BOPA), held in London, UK.