Analytical methods including HPLC, UPLC and HPTLC are presented for the determination of major alkaloid and triterpene saponins from the roots of Caulophyllum thalictroides (L.) Michx. (blue cohosh) and dietary supplements claiming to contain blue cohosh. A separation by LC was achieved using a reversed phase column, PDA with ELS detection, and ammonium acetate/acetonitrile gradient as the mobile phase. Owing to their low UV absorption, the triterpene saponins were detected by evaporative light scattering. The eight triterpene saponins (cauloside H, leonticin D, cauloside G, cauloside D, cauloside B, cauloside C, cauloside A and saponin PE) and the alkaloid magnoflorine could be separated within 35 min using HPLC method and within 8.0 min using UPLC method with detection limits of 10 μg/mL for saponins and 1 μg/mL for magnoflorine. The detection wavelength was 320 nm for magnoflorine and ELS detection was used for the eight saponins. The methods were also successfully applied to analyze different dietary supplements. For the products claiming to contain blue cohosh, there was a significant variability in the amounts of triterpene saponins detected. Calculations based on the analysis results for dietary supplements showed that maximum daily intake of alkaloid and saponins vary with the form (solids/liquids) and recommended doses according to the products label. Intakes varied from 0.57 to 15.8 mg/day for magnoflorine and from 5.97 to 302.4 mg/day for total saponins. LC–mass spectrometry coupled with electrospray ionization (ESI) method is described for the identification and confirmation of nine compounds in plant samples and dietary products. A HPTLC method was also developed for the fast chemical fingerprint analysis of C. thalictroides samples.