Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the gastrointestinal tract. Imatinib mesylate is recommended as adjuvant therapy for GIST after surgical resection. However, drug-related adverse events are common. A 74-year-old female with metastatic GIST who was managed with imatinib experienced severe adverse events, including skin rashes, tremor, and alopecia, etc. The imatinib dose was reduced and the size of the metastatic GIST continued to decrease and adverse events showed significant improvement.