Hunting and consuming wild mushrooms is an increasingly popular avocation, as well as a means of subsistence for certain groups in the United States. Consuming wild mushrooms is relatively safe for persons with the necessary expert knowledge. Each year, however, tragic deaths or illnesses occur when unsuspecting persons ingest toxic mushrooms. We conjectured that there may be vulnerable subgroups that should be targeted for public service announcements and education about mushrooms. Therefore, we reviewed California's hospital discharge database from 1990 through 1994 to ascertain demographic characteristics and outcomes of "serious" mushroom exposures requiring a hospital admission. Children younger than 5 years have a higher rate of hospital admission for "serious" poisonings. Therefore, parents should be reminded of the need for supervising children in areas with wild mushrooms. We did not find evidence that poisoning rates differed significantly between ethnic or racial groups, but this finding may be limited by a failure of these groups to seek care after becoming ill. We discuss briefly the symptoms and treatment of cases of possibly lethal ingestion of amatoxin-containing species of mushrooms.