Flavonoids contained in 70 therapeutic diets served in five hospitals within Hiroshima Prefecture were surveyed to obtain measured amounts (for 28 diabetics, 14 cardiac hypertensives, 14 liver/pancreas/gallbladder diseases, and 14 hyperlipidemics) using high-performance liquid chromatography. Content determination for flavonoids and isoflavones in one day's therapeutic diets indicated 57.3±48.8 mg and 14.1±8.7 mg for diabetics, 36.9±25.0 mg and 11.4±12.7 mg for cardiac hypertensives, 51.4±40.8 mg and 15.8±9.6 mg for liver/pancreas/gallbladder diseases, and, 44.4±44.4 mg and 12.2±10.0 mg for hyperlipidemics, respectively. No significant differences were shown between the kinds of therapeutic diets. Myricetin, daidzein, glycitein, quercetin, luteolin, naringenin, genistein, hesperetin, apigenin, and kaempferol were detected in every therapeutic diets. Incidentally, every therapeutic diets contained a high proportion of hesperetin derived from citrus fruits.