The efficacy and safety of Tai-Kang-Ning (TKN) capsule, a traditional Chinese medicine formula, for the treatment of acute heroin withdrawal syndrome were investigated by conducting a double-blind, double-dummy, positive-controlled, and randomized trial. Sixty-four patients with acute heroin withdrawal syndrome were recruited. These patients were treated with either TKN or lofexidine in a fixed schedule of doses for 10 days. The results indicate that both treatments significantly reduced withdrawal symptoms by day 3, but there was no significant difference overall between lofexidine and TKN in efficacy or safety. These results demonstrate that TKN is effective in the treatment of moderate-to-severe acute heroin withdrawal syndrome with mild adverse effects.