Two pairs of diagnostic primers, IHm01-L/IHm01-H and IHm02-L/IHm02-H, for distinguishing the Chinese crude drug Oviductus Ranae from its substitutes were designed based on sequences of Cyt b gene fragment of the original animals of the drug and substitutes. Total DNAs were extracted from crude drugs purchased from five drugstores in different regions, as well as from original animals of the drug, Rana chensinensis, and seven species of related ranid species. Diagnostic polymerase chain reactions (PCRs) were performed using the two pairs of primers with the total DNAs of the original animals as a template. The result showed that a 240 bp DNA segment was clearly amplified from all templates of Rana chensinensis using primers IHmO1-L and IHm01-H, whereas no DNA band appeared from other templates. While using primers IHm02-L and IHm02-H, we got a clear 140 bp DNA band from all the templates of R. huanrenensis and 3 oviducts of the same species, no PCR product was observed from the other samples. A set of PCR reactions was employed to identify crude drugs from the five drugstores using the two pairs of primers together with HsmL1 and HsmH1 reported in our previous study. The results show that only 20% of the Oviductus Ranae currently sold in markets are qualified products and the rest are not.