OBJECTIVE: This study aimed to investigate the safety and efficacy of Di-Huang-Yin-Zi (DHYZ), also known as Rehmanniae Yin-Zi, a traditional Chinese medicinal formula used for treating of neurological disorders in patients with traumatic cauda equina injury (TCEI). METHODS: In this double-blind, placebo-controlled study, TCEI patients with American Spinal Injury Association (ASIA) impairment grades C were randomized to receive either DHYZ (n = 30) or placebo (n = 30) for 8 weeks. Both groups also received rehabilitation therapy and oral mecobalamine therapy during the treatment. Motor and sensory functions, as well as walking ability, were assessed biweekly. RESULTS: At the end of the treatment, the DHYZ group exhibited significantly higher scores in sensory and motor function, as well as walking ability, compared to the placebo group (all P <
0.05). Additionally, no serious side effects were reported. CONCLUSION: DHYZ has the potential to accelerate nerve repair and may serve as an effective adjuvant therapy to enhance the recovery of nerve function in patients with TCEI.