In this report, we introduce the importance of a system for sharing information about cancer molecular-targeted medicines from trial to the clinic by the department of knowledge education research, department of breast surgical oncology, department of cardiovascular internal medicine and department of dermatology at St. Luke’s International Hospital in Japan.  At present, information regarding the side effect(s) of a study drug does not reach doctors who are not members of the department in charge of the clinical trial.  The reason for this is because clinical trials are conducted under the legal constraints of GCP (Good clinical practice), and while safety information about any adverse events (side effects) is reported, it is limited to the level of an Institutional Review Board.  When there was an enquiry about a known side effect that had occurred to patients taking molecular-target medicine from a doctor who was not a member of the department in charge of the clinical trial, it became clear that information regarding the clinical trial medicine and non-approved medicine was not reaching the clinic.  We developed an original reporting system for such information that would offer the information using the same format as the clinical trial itself, as well as the department in which the side effect was treated, to resolve the problem of access to side effect information outside of the clinical trial itself.  We show that the reporting of such information leads to resolution of this problem.  We believe that this will relieve the patient and contribute to the clinical trial as well as to the department that deals with such side effects.