Efficacy of classic Chinese medicine formula Ditan Decoction () for Alzheimer's disease.

Objective: Determine the efficacy and safety of classic Chinese medicine formula Ditan Decoction (, DTD) for the treatment of Alzheimer's disease (AD) by reviewing the methods and results reported in laboratory and clinical studies in order to suggest strategies for developing more effective drugs for AD.

Methods: Embase (OVID) and China Journal Net (CJN) were searched for articles published between 1947 to November 2011 and 1915 to November 2011 respectively. Articles that fulfilled the inclusion criteria and did not meet the exclusion criteria were collected and compared in terms of research method, interventions and outcomes.

Results: No articles were found in Embase (OVID); 8 were found in CJN (4 laboratory studies; 4 clinical studies). The laboratory studies showed that memory impairment of AD mice models were significantly improved by DTD. The clinical studies showed that Chinese medicine which include DTD, can also relieve the memory impairment of AD patients, however, the data about the exactly effectiveness of DTD was inconclusive.

Conclusions: All the clinical trials have not been fully designed yet. The evidences for recommending DTD in clinical practice were methodologically flawed. Rigid randomization in controlled clinical trials of DTD with adequate blinding and rating methods are highly recommended.