Ninety-seven case samples of marketed shampoo in the Taiwan area were investigated to study the content of zinc pyrithione, cytotoxicity test and skin irritation test. Three of ninety-four. Samples (i.e. 3.09%) were found in violation after being analyzed by U.V. spectrometry. All of samples gave negative results in the cytotoxicity test. Due to the shortage of testing rabbits, only seventy-nine samples of different brands could be done for skin irritation test, in which thirteen cases (16.46%) gave positive results.