A few mouthfuls of liquorice may raise blood-pressure levels, according to researchers from Iceland. Scientists have known for some time that liquorice raises blood pressure however they believed that large quantities were required before any negative effects occurred but according to this latest study "liquorice-induced hypertension is underestimated and could be misunderstood," the study authors commented. Researchers from the Department of Medicine in Sweden and the Department of Chemical Pathology at the University of Iceland set out to investigate the dose-response and the time-response relationship between liquorice consumption and rise in blood pressure. Healthy volunteers consumed liquorice in various doses, 50-200 g/day, for 2-4 weeks, corresponding to a daily intake of 75-540 mg glycyrrhetinic acid, the active substance in liquorice. Blood pressure was measured before, during and after liquorice consumption. The authors noted that systolic blood pressure increased by 3.1-14.4 mm Hg (P < 0.05 for all) and that this demonstrated a dose-response but not a time-response relationship. The individual response to liquorice followed the normal distribution. Since liquorice raised the blood pressure, with a linear dose-response relationship, the authors wrote, even doses as low as 50 g of liquorice (75 mg glycyrrhetinic acid) consumed daily for 2 weeks can cause a significant rise in blood pressure. The scientists stressed that the findings may have important implications for doctors dealing with patients with high blood pressure.