In terms of regulatory toxicology, especially for the traditional Chinese medicines, problems can be arise from a fact that there is no distinctive barrier between herbal drugs and food/beverage. An example is that many kinds of Chinese herbal materials have been also used as tea materials in Korea, China, Japan and Vietnam. Sixteen tea materials (also used as herbal materials) were extracted with 70% ethanol and the extract further partitioned with chloroform and water. Those ethanol extract and fractions were subjected to the SOS-Chromotest to examine potential mutagenicity. It was found that ethanol extract of Chaenomelis Fructus (Chaenomeles japonica Lindley, 木瓜, Rosaceae) and both ethanol extract and water fraction of Cassiae Semen (Cassia tora Linne, 決明子, Leguminosae) showed relatively high mutagenic activities in SOS-Chromotest.