Sakhan, jakhan and takhan are some of Thai common names for Piper species especially for unidentified forest species. They are widely used as vegetables, spices, decoration, traditional medicines and ceremonially. Seven of these species were collected and identified of which the sliced stems are often used as medicinal plants and spices, and are easily preserved as dried powder or slices: Piper betle L. (phlu), Piper colubrinum Link. (prik thai tua phu), Piper nigrum L. (prik thai), Piper pendulispicum C. DC. (jakhan jin), Piper retrofractum Vahl. (dee plee), Piper ribesioides Wall. (takhan lek), and Piper sarmentosum Roxb. (ชะพลู: cha phlu). Stem slices and a powder of what was called sakhan were brought from pharmacies for analysis. The ethnobotany of these species was studied by literature reviews, traditional healers and interviews with locals. DNA barcoding of the main stem from all wild species and slices and powder from pharmacies was performed to provide specific markers which can be standardized for further identification of medicinal sakhan samples. The barcode marker accession numbers are GQ500612-GQ500619 for the rpoC1 gene, GU372746-GU372751 formatK gene, and GQ891994-GQ892001 for trnH-psbA.

Key words: DNA barcodes, ethnobotany, molecular markers, Piper, Thai medicinal sakhan.