Objectives: We evaluated the national prevalence of unnecessary GI drugs in the prescription for the common cold in ambulatory settings and the factors influencing this practice. Method: This cross-sectional study used the National Patients Sample data. We identified patients aged ≥20 years diagnosed with a common cold in a primary care clinic in December, 2018. We investigated whether the prescriptions for common cold of study subjects included any unnecessary GI medications. Demographic and clinical factors influencing the prescription of GI drugs were explored using multiple logistic regression analysis. Results: Unnecessary utilisation of GI medications in treating colds was estimated to be 43.80%. Women were more likely to be prescribed unnecessary GI medications (odds ratio [OR]=1.314). Among physician specialties, paediatricians showed the lowest odds (OR=0.479), whereas surgeons showed the highest (OR=1.655). Patients in urban and rural areas had higher odds than those in the metropolitan areas (OR=1.742). Non-steroidal anti-inflammatory drugs (NSAIDs) use was directly related to unnecessary GI medication prescription (OR=1.903) and the total number of cold drugs prescribed was inversely proportional to unnecessary GI medication use. Patients prescribed three and four or more cold medicines were less likely to receive GI drugs at odds of 0.568 and 0.471, respectively. Conclusion: This study demonstrates the high rate of unnecessary GI medication utilisation in common cold treatment in Korea. Factors influencing unnecessary GI drug utilisation were female sex, physician specialties (surgery), non-metropolitan areas, NSAIDs use, and prescription of fewer cold drugs.