The effects of sour tea (Hibiscus sabdariffa) on hypertension in patients with type II diabetes

To compare the antihypertensive effectiveness of sour tea (ST; Hibiscus sabdariffa) with black tea (BT) infusion in diabetic patients, this double-blind randomized controlled trial was carried out. Sixty diabetic patients with mild hypertension, without taking antihypertensive or antihyperlipidaemic medicines, were recruited in the study. The patients were randomly allocated to the ST and BT groups and instructed to drink ST and BT infusions two times a day for 1 month. Their blood pressure (BP) was measured on days 0, 15 and 30 of the study. The mean of systolic BP (SBP) in the ST group decreased from 134.4±11.8 mm Hg at the beginning of the study to 112.7±5.7 mm Hg after 1 month (P-valu