Abstract: This paper presents the result of library search of 140 heroin cases with the "xjli b. 1b. fs" Ir-Spectrum Database built in the PE 7500 Computer. Statistic analysis showed the following results for the 140heroin cases: heroin was identified as component in 67 cases (47. 86%), in some of which heroin was mainly mixed with caffeine. Some other drugs were found in the rest 73 cases (52. 14%), in which caffeine was often mixed.

Key words: heroin, library search, mixed component