Background: There is a need to develop an evidence base for Chinese herbal medicine (CHM) that is both rigorous and reflective of good practice. This paper proposes a novel methodology to test individualised herbal decoctions using a randomised, double blinded, placebo controlled clinical trial. Method: A feasibility study was conducted to explore the role of CHM in the treatment of endometriosis. Herbal formulae were pre-cooked and dispensed as individual doses in sealed plastic sachets. This permitted the development and testing of a plausible placebo decoction. Participants were randomised at a distant pharmacy to receive either an individualised herbal prescription or a placebo. Results: The trial met the predetermined criteria for good practice. Neither the participants nor the practitioner-researcher could reliably identify group allocation. Of the 28 women who completed the trial, in the placebo group (n = 15) 3 women (20%) correctly guessed they were on placebo, 8 (53%) thought they were on herbs and 4 (27%) did not know which group they had been allocated to. In the active group (n = 13) 2 (15%) though they were on placebo, 8 (62%) thought they were on herbs and 3 (23%) did not know. Randomisation, double blinding and allocation concealment were successful and the study model appeared to be feasible and effective. Conclusion: It is now possible to subject CHM to rigorous scientific scrutiny without compromising model validity. Improvement in the design of the placebo using food colourings and flavourings instead of dried food will help guarantee the therapeutic inertia of the placebo decoction.