Highlights from this report include: for the period January 1986 - December 1988, mentions for cocaine in emergency room (ER) drug-abuse related episodes increased for the total Drug Abuse Warning Network (DAWN) system, and in 20 of the 21 metropolitan areas; no metropolitan areas saw a decrease in cocaine mentions; mentions for heroin/morphine increased in the overall DAWN system, and in 11 of the 21 metropolitan areas; decreases for heroin/morphine mentions were noted in Detroit, Phoenix, and San Francisco; mentions for marijuana increased in the total DAWN system and 14 of the 21 areas, while no significant decreases were noted in any of the metropolitan areas; the whole DAWN system noted increases in PCP/PCP combinations, especially in Baltimore, St. Louis, and Washington, DC, while 3 areas showed decreases in PCP/PCP combination mentions. In drug-abuse related medical examiner (ME) cases, drug abuse deaths involving cocaine increased from 381 as of December 1985 to 988 as of June 1988; and heroin/morphine mentions increased from 746 as of December 1985 to 827 as of June 1988. This report presents trends in the semiannual number of mentions of selected drugs in ER drug-abuse related episodes for the period January 1986 - December 1988 and drug-abuse related ME cases for the period July 1985 - June 1988, as reported through the DAWN system. Data were obtained from 597 participating ERs in 21 metropolitan areas and 79 MEs or coroners in 26 metropolitan areas in the continental United States. Trends in drug mentions are tabulated for 6-month intervals over a 3-year period. Tables and appendixes