We aimed to analyze the effects of a large-scale infection on the prescription drug use. Using the data of 1,000 randomly selected people from the National Health Insurance Corporation sample cohort 2.0 data, we analyzed prescription drug data before and after the 2009 novel swine-origin influenza A (H1N1) and 2015 middle east respiratory syndrome (MERS) outbreaks. Drugs were grouped and converted into ATC codes, and then the changes in consumption between pre & post-period along with the drug efficacy groups (ATC code) were analyzed by age groups (subjects aged 65 years or above vs. subjects aged under 65 years). Analysis results were expressed as frequency, percentage (%), and mean± standard deviation. Data analysis was performed using open source program R. As results, in the H1N1 influenza situation, in group C (cardio-vascular system), group M (musculo-skeletal system), group N (nervous system), and group S (sensory system) showed a statistically significant increase. In case of MERS, only in group C (cardio-vascular system) showed a statistically significant increase. In particular, the use of drugs in group C (cardio-vascular system) increased in the age group of 65 years and older, and the use of drugs such as group N02 (analgesic drugs) increased in the age group of ...