Two cases of drug abuse have been described, the persons concerned being adolescent youths. In the first case, separate episodes of formication and Lilliputian hallucination occurred; in the second case, an episode of Lilliputian hallucination occurred. Although both these youths took other drugs, amphetamine-drugs appeared to be the dominant drugs and therefore the probable cause of the hallucinatory phenomena described. Attention has been drawn to the marked similarity which obtains between the effect of cocaine—on the one hand, and amphetamine-drugs—on the other. The writer has suggested that in future, addicts may substitute intravenous methylamphetamine for intravenous cocaine.