Preliminary Study on Safety and Efficacy of a Thai Herbal Remedy in Persistent Allergic Rhinitis: A Randomized Double-blind Placebo-controlled Trial

Background: Globally, the prevalence of allergic rhinitis has increased significantly. However, herbal remedies for allergic rhinitis were recorded on Wat Pho’s marble inscription in 1832, yet have never been scientifically studied. Objective: To identify the safe and appropriate dose of an herbal remedy comprising six herbs in healthy adults, and to explore the safety and preliminary efficacy of the remedy. Materials and Methods: Phase I, a randomized, non-blinded study focusing on safety of the studied drug included 16 healthy participants. Phase IIa, a randomized, double-blind, placebo-controlled trial, included 44 patients with persistent allergic rhinitis. Results: Generally the Thai herbal remedy was safe. However, diarrhea was reported significantly move often in the group that received the remedy than in the placebo group (p = 0.029). The appropriate dose was determined to be two capsules (1.12 g) after meals, three times per day. Preliminary efficacy according to symptom-score evaluation by a physician revealed significant improvements in 3 symptoms. The more than 25% improvement in peak nasal inspiratory flow was detected in participants who received herbal remedy (p = 0.018). Conclusion: This herbal remedy was well tolerated, with a somewhat increased occurrence of diarrhea. Although the study showed some symptom improvement. Keywords: Thai herbal remedy, Allergic rhinitis, Clinical trial, Safety, Efficacy