RESUMO
To analyze and discuss placebo-related information in clinical research literatures in the past 30 years, including placebo's dosage form, ingredients, preparation process and quality control. Effort were made to research the CNKI. full-text database to preliminary find 700 placebo-related clinical research literature, screen out 301 eligible articles by hand, read the literatures to extract placebo-related information and make statistics and discussions. According to the results, Chinese randomized placebo-controlled clinical studies were characterized by diverse dosage forms of placebo with lack of reports for components, as evidenced by the only 17 literatures describing placebo's preparation or specific composition among the 301 literatures. Placebo-controlled clinical trials covered a wide range of disease spectra, but with a specific tropism of diseases in terms of system classification. Although placebo plays a key role in blinded clinical studies, researchers made less records of placebo, perhaps because they paid less attention to placebo or more attention to the research process or restricted by other objective conditions. Moreover, placebo production, quality control and quality evaluation also need to be further standardized.