Marijuana use rose sharply in 1994, the third year of increase for 8th graders and the second for 10th and 12th graders. Daily marijuana use rose significantly in all three grade levels in 1994, reaching 3.6 percent among seniors. Continued increases were also noted in the use of stimulants and inhalants. The overall prevalence of crack cocaine leveled in 1987, but annual prevalence rose slightly in 1994. Cocaine use began to decline a year earlier than crack, and perceived risk continued to decline among 8th and 10th graders in 1994 but rose slightly among seniors. PCP use fell sharply among high school seniors between 1979 and 1982, from an annual prevalence of 7 to 2.2 percent, and reached a lower point of 1.6 percent in 1994. The annual prevalence of heroin use by seniors was relatively steady, but 8th graders showed a significant increase from 0.7 percent in 1993 to 1.2 percent in 1994. Barbiturate use declined to 3.2 percent in 1988 and rose significantly to 4.1 percent in 1994. Males were generally more likely than females to use most illicit drugs. Alcohol use did not increase as the use of other illicit drugs decreased, and no statistically significant changes were observed in drinking prevalence during 1994. Cigarette smoking by secondary school students increased in 1994, and the initiation of daily smoking most often occurred in grades 6 through 9. Black students had consistently lower drug use rates than white students. Among seniors, Hispanics had the highest drug use rates for most dangerous drugs. Trends in secondary school drug use are discussed in terms of attitudes and beliefs about drugs and the social milieu in which drug use occurs. Appendixes contain additional information on drug use prevalence and student demographic characteristics. 53 footnotes, 74 tables, and 38 figures