Research on moxibustion separates three effects: the thermal effect of local heating, the radiant effect of infrared and near-infrared emission, and the chemical effect of the smoke and volatiles. Each has been measured, and each has been proposed as the principal mechanism.
Clinical evidence is more limited than for acupuncture, partly because moxibustion is harder to sham. The strongest findings concern pain, gynaecological conditions and immune markers, with much of the work coming from China and requiring independent replication. The smoke is a genuine concern in clinical settings and is the reason extraction systems are now standard in Chinese hospitals.