The aqueous extracts and ethanol precipitates of aqueous extracts of 18 medicinal herbs traditionally used in China were screened for their ability to inhibit human immunodeficiency virus type-1 reverse transcriptase (HIV-1 RT) in-vitro. Among the samples screened at a concentration of 500 microg mL-1, dried rose (Rosa rugosa) flowers showed the strongest inhibition. The ethanol precipitate of the aqueous extract of R. rugosa was processed and two components (P1 and P2) were obtained after ion exchange chromatography on DEAE-cellulose. Then, P1-a (Mr 150 kDa) and P1-b (Mr 8 kDa) were isolated from P1 by gel filtration on Sephadex G-200. They inhibited the activity of HIV-1 RT with an IC50 of 158 nM and 148.16 microg mL-1 (18.5 microM), respectively. Further structural analyses revealed that P1-a was a polysaccharide-peptide complex, and P1-b was a polymer consisting of acteoside and acteoside derivatives identified by Fourier transform infrared spectroscopy, nuclear magnetic resonance, assays of carbohydrate and protein contents and high-performance liquid chromatography electrospray ionization mass spectrometry.