In order to minimize such adverse drug reactions, governments and international organs have been on the watch for them. Also in South Korea, a system has been established in order that adverse drug reactions may be reported to Korea Food and Drug Administration(KFDA). This study is to analyze drugs to cause adverse reactions, the adverse reactions and patients concerned on the authority of the data of Korea FDA, which is expected to be the preliminary data on preventable adverse reactions. This study was conducted on the 74,037 cases of adverse drug reactions reported to Korea FDA between January 2007 and June 2010. Fentanyl, iopromide and tramadol caused adverse reactions with high frequencies. Oseltamivir showed a high frequency between 2009 and 2010 due to the influence of the new influenza A. Also, OTC drugs accounted for approximately 5% of the adverse reactions. In 2009, adverse drug reactions remarkably increased (2,106 cases; 10.1%) in infants and children due to the new influenza-A(H1N1). The patients aged between 31 and 64 accounted for approximately 55% during the given period. There was no significant intergender difference. In relation to regions, the adverse reactions most frequently occurred in the gastrointestinal system and the integumentary system for three and half years. In addition to anticancer drugs and immunosuppressive drugs that are known to cause adverse reactions frequently, not a few of OTC drugs and external preparations caused such reactions. In particular, the drugs containing specific ingredients caused adverse reactions more frequently than others from 2007 until the first half of 2010. It is advisable for prescribers to acquaint themselves with such adverse reactions and to prescribe drugs other than them. They also have need to sensibly cope with adverse drug reactions just in case they have no substitute drugs. In addition, patients also need to be trained to understand possible adverse reactions in order that they can sensibly accommodate them or choose healthcare services. The results of this study are expected to be helpful to minimize adverse drug reactions.