Liquorice root has been used medicinally for many years to treat dry cough, asthma, hunger, thirst, sterility of women, fever, digestive problems and pathologies of organs such as lungs, stomach, intestines and kidney. Glycyrrhetinic acid (one of the active constituents in liquorice) has diverse in vitro effects as an inhibitor of 11β hydroxysteroid dehydrogenase (11HSD), 5α reductase and hormone receptor binding. The aim of this study is to investigate the effects of moderate daily consumption of liquorice sweets on salivary DHEA and testosterone levels in healthy individuals. Ten men and 10 women (1830 years) were given 100 g liquorice sweets (containing 3 g of liquorice extract) per day or non-liquorice containing confectionary for 7 days in a crossover study. Sensitive and specific ELISA methods were used to measure total (free plus conjugated) steroid levels following ether extraction of saliva samples collected at 08000900, 11001300 h and 17001900 h of the final day of each arm of the study. Free and conjugated levels were also measured separately in a second aliquot of saliva after fractionation using C18 Sep-Pak cartridges (Waters). Conjugated steroids were first hydrolysed by incubation with extracts of Helix pomatia. Other steroid hormones such as aldosterone, cortisol and cortisone were also estimated. Changes in cortisol, cortisone and aldosterone confirmed expected effects on 11βHSD activity. Liquorice increased total and free DHEA levels in both males and female saliva (P<0.01) by 48.3 and 56.9% respectively. Testosterone levels were also higher perhaps due to peripheral conversion of DHEA. However, conjugated DHEA levels were decreased by liquorice. Since conjugated DHEA is predominantly DHEA sulphate, which is synthesized in the adrenal gland, we suggest that the opposing effects of liquorice on free and conjugated DHEA reflect inhibition of DHEA sulphation. GA or another component of liquorice could be an inhibitor of the adrenal sulfotransferase enzyme SULT2A1. This represents a novel target in the control of adrenal steroid hormone secretion.