Our study aim to understand complete picture and issues on medical safety and investigate preventive measures for medical errors by analyzing data captured by bar code system and entered by Personal Digital Assistance. Barcode administration system named Point-of-Act-System was designed to capture every activity at the bed sides. Complete activity data including injection, treatment and other nurses' activity and warning data showing mistakes on injections were used for our analyses. We described the data and analyze statistically by accumulating data by hour to find potentially risky time and understand relationship between business and errors. The warning rate as a whole was 6.1% in average. The result showed there was a negative correlation between number of injections and injection warning rate (-0.48, p<0.05). Warning rate was relatively low in the hours that numbers of administrating injections are high. Bar code administration system is quite effective way not only to prevent medical error at point of care but also improve patient safety with analyses of data captured by them.