A new type of heroin has increased in frequency in the San Francisco Bay Area in the past three years. "Persian" heroin, coming to this country from Southwest Asia, differs from commonly-seen heroin in several ways: (1) distinctive marketing channels, (2) different routes of administration, (3) increased purity, (4) more severe withdrawal, and (5) different demographic characteristics of users. "Persian" heroin users tend to be younger and more likely to be White and unemployed as compared to other heroin users.