AbstractBackground:Molecular targeted anticancer drugs such as multikinase inhibitors have shown obvious therapeutic advantages in a variety of tumors. The occurrence of hand-foot skin reaction (HFSR) is positively correlated with therapeutic effect, but it is also the most common cause of dose limiting toxicity for this treatment. This can lead to interruption or decrement of the treatment, a reduction in quality of life for patients, as well as potentially leading to secondary infections. As a result, the curative effect of targeted anticancer drugs will be negatively impacted. Currently, there is no certain and effective therapy. External use of Chinese herb medicine LC09 in the early treatment of HFSR has shown positive outcomes, but it is necessary to carry out further clinical research to confirm.Objectives:The purpose of this study was to investigate the efficacy and safety of topical soaks of Chinese herbal medicine LC09 for HFSR induced by molecular targeted anticancer drugs.Methods:The trial is a prospective, randomized, controlled, double-blind, monocentric, and interventional study. A total of 66 patients with HFSR will be recruited and randomly assigned to receive either LC09 Granules or placebo. The primary outcomes are the assessment of HFSR grade and pain score. The secondary outcomes are the evaluation of the quality of life, incidence of targeted drug dosage reduction, and incidence of targeted drug withdrawal.Discussion:This prospective, randomized clinical trial will provide valuable data regarding the efficacy and safety of topical soak treatments with LC09 granules for HFSR. Positive results would provide evidence-based complementary therapeutic approach future treatments of HFSR.Trial registration:Chinese Clinical Trial Registry, http://www.chictr.org.cn, ChiCTR1900023679. Registered on 7 June 2019.