Glycyrrhetinic acid (GA) is the active metabolite of glycyrrhizic acid, one of the components of liquorice extract. It has been shown to possess anti‐inflammatory activity and to inhibit hepatic tumour growth. In this preliminary study, we have shown that GA could significantly reduce the rate of proliferation of LNCaP androgen dependent prostate cancer cells, whereas it had no effect on proliferation of PC3 and DU145 androgen‐independent prostate cancer cells. Additionally, GA could significantly reduce the production of prostate‐specific antigen by LNCaP cells maintained in‐vitro. This study provides a sound platform for further investigation.