Efficacy and Safety of Ecklonia cava Kjellman Extract Complex in Respiratory Health: A Randomized, Double‐Blind, Placebo‐Controlled, Multicenter Clinical Trial

ABSTRACT Industrialization, air pollution, and respiratory infections have highlighted the importance of maintaining respiratory health. Ecklonia cava Kjellman (EC) has anti‐inflammatory, antioxidative, and anti‐allergic effects and therapeutic potential for respiratory symptoms. We evaluated the efficacy and safety of Ecklonia cava Kjellman extract complex (EEC), composed of EC and Chrysanthemum indicum Linnaeus ( C. indicum ) extract, in respiratory health. A randomized, double‐blind, placebo‐controlled, multicenter clinical trial was conducted. Participants ( n = 106) were randomly allocated to the EEC and placebo groups at a 1:1 ratio and administered EEC or placebo twice daily for 12 weeks, with four visits (screening and weeks 0, 6, and 12). Breathlessness, cough, and sputum scale (BCSS), pulmonary function test (forced vital capacity (FVC), forced expired volume in 1 s (FEV 1 ), and FEV 1 /FVC), St. George's respiratory questionnaire (SGRQ), visual analogue scale (VAS), and modified Medical Research Council dyspnea scale (mMRC) were assessed. BCSS (total, breathlessness, and sputum scores), FEV 1 , and VAS (cough and sputum) were significantly improved in the EEC group compared with the placebo group. No significant differences in SGRQ and mMRC between the groups. Safety assessments showed no severe adverse events or clinically significant changes. Given the established pharmacological mechanisms of EC, including its anti‐inflammatory, antioxidative, anti‐allergic, and antimicrobial effects, the results of this study support the potential of EEC for relieving respiratory symptoms and improving respiratory health.