Oregon health department officials were notified of a cluster of E. coli O157:H7 cases in the city of Bend. Food histories of the case-patients pointed to McGrath's Fish House Restaurant as a common source of exposure. Five food workers were among those who had reported symptoms. A case control study implicated parsley served in food or as a garnish. Oregon health investigators traced the source of the fresh parsley served at the restaurant to the same Oregon farm that had supplied parsley to the Olive Garden and to the Boat Shed restaurants in Washington state. These restaurants had also experienced outbreaks of E.coli O157:H7.