The ultraviolet absorption spectra of berbines and cp-berbines consist of a single, weak and narrow band in which l\maQl position dependeds on the kind of auxochrome group i . e. 1 methylenedioxyor dimethoxy group attached to 2-3 position. The effect of the auxochrome group at 11-12 position or 12-13 position is very small.The shape of the band of oxyberberine , oxy-e-berberine and oxyprotoberberine are similar1 especially those of the latter two substances resemble closely, Comparing with i soquinoline , the bands (b), (c) and (d) of G-berberines and protoberberine are considered as characteristic of isoquinoline structure, while the band (a) in visible region is of berbermium structure, however. the absorption curve of (,O-berberines does not show any characteristic of isoquinoline or· berberinium structure.The ultraviolet absorption spectrum of berberine itself has been most thoroughly studied and only a brief statement has been found for palmatine, coptisine, oxyberberine, and oxypalmatine. On the contrary, very detailed studies were made on the ultraviolet spectra of almost all of tetrahydroberberines, i, e. tetrahydroberberine. tetrahydro-e-berberine, tetrahydropalmatine, tetrahydrocoptisine, and tet rahydro-e-coptisine.In the present study, ultraviolet spectra were determined on a Hitachi Model 139 spectrophotometer and autorecor ding spectrometer Model EPS-3. The spectra 'were generally taken in methanol 135