Eighty-seven healthy volunteers ingested a purple-fleshed sweet potato beverage with various contents of anthocyanin (beverage A; 22.1 mg/250 ml, B; 107.8, C; 84.9). An acylated anthocyanin, peonidin 3-caffeoylsophoroside-5-glucoside, was detected in the urine 2 h after ingestion. The concentrations were 15.1+/-2.2 microg/l of urine (mean+/-SEM), 46.6+/-5.3, and 53.3+/-2.2 for beverages A, B, and C respectively.