Heroin dependence is one of the major health issues worldwide. Methadone Maintenance Therapy (MMT) is an effective treatment for opioid dependence, but more than three quarters of persons receiving MMT report sleep complaints. Traditional Chinese Medicine (TCM) is one of the most common complementary therapies offered to insomnia patients in Taiwan. Investigators designed a randomized, double-blind, placebo-controlled clinical trial to evaluate the efficacy of TCM in methadone-maintained persons with sleep disturbance.