The incidence of death from poisonous substances in Massachusetts was reviewed for the 10-year period 1955-64 & compared with 2 earlier 10-year periods–1928-37 & 1938-48, studied with identical methods. Deaths from poisoning, alcohol & illuminating gas declined for the later period while those from carbonmonoxide remained practically unchanged. Only deaths from barbiturates steadily increased during the period 1955-64. Suicidal deaths were highest for barbiturates (82.8%) followed by CO (75%)