OBJECTIVE: To study the pharmacokinetics and relative bioavailability of combination Angelica sinensis (Oliv.) Diels and Piper nigrum L.. METHODS: The content of ferulic acid in plasma was determined directly by HPLC after an oral administration of Piper nigrum L. in combination individually with Angelica sinensis (Oliv.) Diels. The plasma concentration-time curves were plotted. The main pharmacokinetic parameters and relative bioavailability were obtained. RESULTS: The plasma concentration-time curve of Ferulic acid was discribed by an one-compartment model. The relative bioavailability of Piper nigrum L. combined with Angelica sinensis Diels was 169.03%. CONCLUSION: By the statistical analysis, Piper nigrum L. combined with Angelica sinensis (Oliv.) Diels can increase the relative bioavail-ability of Ferulic acid.