BACKGROUND: Anorexia is a common cause of malnutrition and is associated with negative effects on the quality of life (QOL) for patients with cancer. Management of appetite is the key to improving both the QOL and the prognosis for such patients. Yukgunja-tang (YGJT) is a traditional herbal medicine extensively prescribed in Korea as a remedy for various gastrointestinal syndromes. Currently, no standardized herbal medicine treatment exists for patients with cancer who are suffering from anorexia after surgery, chemotherapy, and/or radiotherapy. For that reason, this study aims to examine the efficacy and the safety of using YGJT to treat anorexia in such patients and to establish whether or not YGJT can be recommended as the primary therapy. METHODS: We will enroll 52 cancer patients diagnosed with anorexia. The enrolled participants will be randomly allocated to 2 groups: The control group will receive nutrition counseling, and the YGJT group will receive nutrition counseling and be administered YGJT at a dose of 3 g twice a day for 4 weeks (a total of 56 doses of 3.0 g per dose). The primary outcome of this study is the change in the score on the anorexia/cachexia subscale (A/CS) of the Functional Assessment of Anorexia/Cachexia Therapy (FAACT). The secondary outcomes are the changes in the FAACT score with the A/CS score excluded, the score on the Visual Analogue Scale (VAS) for appetite, the weight and the body mass index (BMI), and laboratory tests for compounds such as leptin, tumor necrosis factor-α (TNF-α), ghrelin, and IL-6. All variables related to the safety assessment, such as vital signs, electrocardiography results, laboratory test results (CBC, chemistry, urine test), and adverse events, will be documented on the case report form (CRF) at every visit. CONCLUSION: This study is the first randomized controlled trial to investigate the efficacy and the safety of using YGJT for treating patients with cancer-related anorexia in Korea. We designed this study based on previous research about YGJT. This study will serve as a pilot and provide data for planning further clinical trials on herbal medicine and cancer-related anorexia. TRIAL REGISTRATION: Clinical Research Information Service (CRIS), Republic of Korea, ID: KCT0002847. Registered retrospectively on 3 April 2018.