Rapidly repeated imaging of the left middle fingertip skin blood perfusion was performed in 51 healthy volunteers (mean age +/- SD: 25.3 +/- 7.6 years) prior to, immediately after and in the early reperfusion phase following introduction of an acupuncture needle at the Neiguan point (Pe. 6) and at a placebo point respectively, using a Laser Doppler Perfusion Imager (LDPI). The average skin perfusion of the fingertip was calculated for each image and used as an indicator of the microvascular response to the acupuncture needle introduction. The results of this randomised, placebo-controlled, cross-over study showed significant differences (p < or = 0.001) in the immediate skin blood perfusion response when needling is performed in an acupuncture point (Neiguan) and a placebo point, with a more pronounced reduction in skin blood perfusion when needling the acupuncture point. In the early reperfusion phase, however, a substantial increase in skin perfusion was observed that amounted to about 18% of the level prior to needle introduction, irrespective of the site of needle application. In a single individual it was demonstrated that the vasodilatation following needling in the acupuncture point persisted for a more extended time period. These results suggest that the LDPI technology may be useful in visualising and quantifying the peripheral vascular effects of acupuncture on the microcirculation.