Mixture of Arnebia euchroma and Matricaria chamomilla (Marhame-Mafasel) for pain relief of osteoarthritis of the knee - a two-treatment, two-period crossover trial

紫草（Arnebia euchroma）和洋甘菊（Matricaria chamomilla）混合物（Marhame-Mafasel）治疗膝骨关节炎疼痛的疗效——一项两阶段、两周期交叉试验