For the purpose of investigation on adulteration of synthetic chemical drugs in Chinese cough syrup preparations, the Bureau randomly collected 99 samples from Sep. 1985 to May 1986 in Taiwan area. The results of thin-Layer chromatography and U V spectrophotometry analysis indicated 11 samples (11.1%) were adulterated with synthetic drugs including Acetaminophen. Guaiacol Glyceryl Ether and Chlorpheniramine Maleate. Among the three components, Chorpheniramine Maleate is the most highly adulterated one. 8 samples were adulterated with it. The result of 11.1% is lesser than result (31.3%) of 1985 and the adulterated components are similar to the adulterated component of 1985.