Medicinal plant markets not only provide a snapshot of a country's medicinal flora, they also reflect local health concerns and the importance of traditional medicine among its inhabitants. This study aimed to describe and quantify the Ghanaian market in herbal medicine, and the diversity of the species traded, in order to evaluate their economic value. Initial visual surveys on the markets were followed by a detailed quantitative survey of 27 stalls in August 2010. Market samples were processed into herbarium vouchers and when possible matched with fertile vouchers from the field. We encountered 244 medicinal plant products, representing 186-209 species. Fourteen species were sold at more than 25% of the market stalls. Seeds and fruits that doubled as spice and medicine (Xylopia aethiopica, Monodora myristica, Aframomum melegueta) were in highest demand, followed by the medicinal barks of Khaya senegalensis and Pteleopsis suberosa. Plants sold at the market were mostly used for women's health, in rituals, as aphrodisiacs and against sexually transmitted diseases. An estimated 951tons of crude herbal medicine were sold at Ghana's herbal markets in 2010, with a total value of around US$ 7.8 million. Between 20 and 30% of the Ghanaian medicinal flora was encountered during this survey. Roots were less dominant at the market than in dryer parts of Africa. Tons of Griffonia simplicifolia and Voacanga africana seeds and Fadogia agrestis bark are exported annually, but data on revenues are scanty. None of these species were sold on the domestic market. Our quantitative market survey reveals that the trade in Ghanaian herbal medicine is of considerable economic importance. Regarding the specific demand, it seems that medicinal plants are used to complement or substitute Western medicine. Further research is needed on the ecological impact of medicinal plant extraction. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.