Objective: To compare the chemical compositions between Dendrobium candidum (D. candidum) and Dendrobium nobile (D. nobile).
Method: Relative area and content of every chromatographic peak in the ammonic chloroform extracts of D. candidum were compared with those of D. nobile with high performance liquid chromatography-mass spectrometry.
Results: The relative area of alkaloids accounted for 2.34% and 41.87% in D. candidum and D. nobile, respectively. The relative area of 25 identical compositions took up 97.12% in the total area of D. candidum and 50.09% in that of D. nobile, and contents of 23 composition were higher in D. candidum than those in D. nobile.
Conclusions: The quantity and contents of alkaloids are remarkably different between D. candidum and D. nobile. However, D. candidum has a higher quality than D. nobile in terms of the same chemical compositions.