More than 700,000,000 prescriptions are issued every year for the approximately 18,000 pharmaceutical products in Japan. Consequently, numerous measures have been implemented to ensure the safety and efficacy with which these large quantities of drugs are managed. One of these approaches is the PreAVOID report, which focuses on the prevention and avoidance of adverse reactions and drug interactions by collect- ing and analyzing pharmaceutical care reports compiled by hospital pharmacists. According to the Japanese Society of Hospital Pharmacists, more than 20,000 such reports are issued annually. These reports are screened for abnormal clinical test values to identify which adverse reactions occur at the highest frequencies. While many hospital pharmacists scrutinize these laboratory test sheets, the awareness of clinical laboratory specialists regarding prescribed medicines is not known. We therefore invited specialists who are well versed in matters related to pharmaceutical risk management to this symposium to present the latest topics related to the influence of prescribed medicines on laboratory test values, and to discuss current issues asso- ciated with monitoring adverse events and adverse reactions. In addition, we examined potential strategies for avoiding severe adverse effects by establishing specialist teams and the role of laboratory specialists on such teams. [Review].