Liquorice-induced rise in blood pressure: a linear dose-response relationship

J Hum Hypertens. 2001 Aug;15(8):549-52. doi: 10.1038/sj.jhh.1001215.


To clarify the dose-response and the time-response relationship between liquorice consumption and rise in blood pressure and explore the inter-individual variance this intervention study was designed and executed in research laboratories at University hospitals in Iceland and Sweden. Healthy, Caucasian volunteers who also served as a control for himself/herself 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. Systolic blood pressure increased by 3.1-14.4 mm Hg (P < 0.05 for all), demonstrating 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, 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 finding of a maximal effect of liquorice after only 2 weeks has important implications for all doctors dealing with hypertension. There does not seem to be a special group of responders since the degree of individual response to liquorice consumption followed the normal distribution curve.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Analysis of Variance
  • Blood Pressure / drug effects*
  • Confidence Intervals
  • Dose-Response Relationship, Drug
  • Female
  • Follow-Up Studies
  • Glycyrrhiza / adverse effects*
  • Heart Rate / drug effects
  • Humans
  • Hypertension / chemically induced*
  • Iceland
  • Male
  • Plants, Medicinal*
  • Potassium / blood
  • Reference Values
  • Regression Analysis
  • Sweden
  • Time Factors


  • Potassium