Parkinson's disease (PD) is a neurodegenerative disease, where treatment with medication may lead to gastrointestinal (GI) symptoms. The objective of this case study was to investigate the effectiveness of Korean medicine (KM) in treating PD with drug-induced GI dysfunction. A 70-year-old female participant was diagnosed with PD in 2010 and drug-induced gastritis in 2016. Her major symptoms were related to GI, PD, and overall feeling of weakness. She was treated with KM including pharmacopuncture, acupuncture, moxibustion, and herbal medicines, in combination with Western medicines during 46 days of in-patient care. This study showed an improvement in symptoms and scores on the GI symptom scale, Unified Parkinson's disease rating scale, Hoehn and Yahr staging, Berg balance scale, PD quality of life, and stress index at discharge. This case demonstrated that the symptoms of drug-induced GI dysfunctions in PD was improved by treatment with KM.