1 During 1978--1980 general toxicological investigations were performed on specimens from 211 patients (62 male, 149 female) aged 65 years and over. 2 The investigations were an important factor in establishing the diagnosis in 32 of 91 (28 male, 63 female aged 65--92 years, median 73 years) poisoned patients, most (75) of whom had deliberately taken overdoses. 3 Seventy-one patients were severely poisoned (grade 3--4 coma) and 10 died. Benzodiazepines (49%) and barbiturates (43%) were the drugs encountered most frequently, although 54% had ingested more than one pharmaceutical preparation. 4 In the survivors the depth of coma was usually greatest in patients poisoned principally with barbiturates, whilst the duration of coma and the incidence of respiratory complications were greater in those poisoned with benzodiazepines. However, there was considerable variability in the depth and duration of coma associated with a given initial plasma concentration within both groups. 5 Although general toxicological investigations can provide useful diagnostic information when poisoning is suspected in elderly patients, unequivocal interpretation of the results obtained is not always possible.