Objective To explore the effect of Qing-Fei-Pai-Du decoction (QFPDD) on the friction of different bracket systems, in order to provide a reference for the treatment of orthodontic patients infected with Corona Virus Disease 2019 (COVID-19) using QFPDD. Methods A total of 54 premolar active self-ligating brackets (GAC In-ovation),passive self-ligating brackets (Damon Q) and traditional ligating brackets (Shinye standard mesh straight wire arch brackets) were selected and compared with 3M stainless steel wires [0.018 inch (1 inch=2.58 cm) round wire; 0.018 inch×0.025 inch and 0.019 inch×0.025 inch square wire] with different sizes to form a friction mechanics system. The bracket systems were immersed in QFPDD and artificial saliva respectively, and then transferred to the universal mechanical testing machine for friction measurement. The characterization of stainless steel wire after soaking in different media was observed under scanning electron microscope, and the accumulation degree of debris on the surface of arch wire after soaking in QFPDD and artificial saliva was clarified. A two-way ANOVA analysis of variance was used for statistical analysis. Results There was no significant difference in the friction force of the bracket system composed of GAC In-Ovation, Damon Q and 0.018 inch stainless steel round wire under two different media immersion (P>0.05),while the friction of two self-ligating brackets increases under the medium of traditional Chinese medicine with 0.018 inch×0.025 inch and 0.019 inch×0.025 inch steel square wire (P<0.001). The friction force of the new sub-standard straight wire arch bracket under QFPDD medium immersion increased after ligation with three kinds of arch wires, and the difference was statistically significant (P<0.01). In addition, the friction force of traditional ligation brackets was significantly higher than that of self-locking brackets in both media (P<0.001). The friction force of GAC In-Ovation was greater than that of Damon Q in the two stainless steel square wire states. After immersion in QFPDD, a large amount of debris adhesion could be observed on the surface of the arch wire under scanning electron microscope. Conclusion The friction of the bracket system under QFPDD medium is enhanced, and the suspended matter in the decoction will deteriorate the debris accumulation on the surface of the arch wire. Orthodontic patients taking QFPDD and other traditional Chinese medicine decoctions may require relatively special oral care measures. [ABSTRACT FROM AUTHOR]