Quality of moxa wool contained in commercial moxibustion devices: test method and examples of waste particle concentration

Background: Moxibustion treatment involves a combination of thermal and chemical stimulation applied by the combustion of moxa wool. The quality of moxa wool is considered to be an important factor in moxibustion treatment traditionally and clinically. However, despite its importance, quantitative and objective methods for determining moxa wool quality are lacking. Methods: Moxa wool and commercial indirect moxibustion (CIM) device specimens were randomly collected, dried and strained through sieves of various sizes for 10 h. After sieving, the residues remaining on each sieve were collected. The collected samples were weighed and microscopically observed. Results: In this study, we observed that fibres mainly remained on sieves sized 425 μm, and particles were smaller than 300 μm. The residues between 425 and 300 μm varied between the products. In addition, moxa wool for direct moxibustion (DMW) exhibited significantly more fibres than moxa wool for indirect moxibustion (IMW). Most of the CIM devices using moxa wool had a quality similar to IMW, except for one CIM brand using moxa wool that contained three times more waste particles than IMW. Conclusion: Based on the results of this study, we conclude that the sieving method is useful for testing the quality of moxa wool even after the CIM manufacturing process. The sieve sizes of 425 and 300 μm could be used as a yardstick to determine the quality of moxa wool. Although this approach requires larger scale validation against existing standard methodologies, we believe it has great potential to be used to improve and safeguard the quality of moxa wool contained in commercial moxibustion devices.