Fig. 1

Study design. (a) Patient disposition; (b) study design; (c) study agent and placebo. The Indigo naturalis ointment used was a mixture (1:10) of Indigo naturalis powder and vehicle (Vaseline, microcrystalline wax, and olive oil [5:6:9]). Placebo preparation used was a mixture of blue dye powder (Indigo carmine aluminum lake [Blue #2] and Allura red AC aluminum lake [Red #40]) and vehicle