Poison Control Centers
Poisoning
Regional Medical Programs
Coroners and Medical Examiners
Mushroom Poisoning
Hotlines
Physicians' Offices
Drug Overdose
San Francisco
Emergency Service, Hospital
Poisons
Retrospective Studies
Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.