The loss of essential oil during infusing Anchu-san was examined. After six minutes boiling, 22.7% of oil passed into the decoction and only 7.8% of oil remained when infused till half volume.
The contents of essential oil in diverse preparations of Anchu-san on the market were also compared to find that all of the medicines contained far less oil than decoction.
Then, simultaneous analysis of essential oils in Cinnamomi Cortex, Foeniculi Fructus and Amomi Semen, which constitute Anchu-san, by using high-performance liquid chromatography was investigated. The constituents of oils, cinnamaldehyde, D-camphor, borneol, linalool,
anethole and bornyl acetate, were separated by using μ-Bondapak C13 as column and water: methanol (40: 60) as eluate. From the patterns of chromatograms of the decoction and several preparations, some new informations were provided.

The decocted extract of Uncariae Ramulus et Uncus, for which prolonged boiling is presumed to reduce its activities, was extracted with n-hexane-chloroform (5: 1) and methanol consecutively. The patterns of each organic solvent extract were analysed with thinlayer chromatography (TLC) by several solvent systems using the Dual-wavelength TLC Scanner. No clear difference in the patterns was evident in any of the 10-120 min decocted extracts.
The comparison of patterns of the chromatograms however revealed some new informations.

Weights of extracts, ultra violet absorption spectrum, thin-layer chromatography and proton nuclear magnetic resonance spectrum were used for discrimination of occurrence of reaction between constituents of a pair of crude drugs during decoction.
Distinction in the examination heads above mentioned between individual decoction and simultaneous decoction were investigated. A few of pairs were found to have some changes and these observations indicated possibility of the reactions of constituents in the crude drugs.

The changes of contents of dehydrocostuslactone (I) and costunolide (II) in the extract of Saussureae Radix were investigated during decoction. The contents of I and II in infused solution were reached to maximum after about 10min of the decoction, respectively. However, when the decoction was continued until the volume becomes to half, the contents of I and II in the solution decreased significantly compared to maximum content in the decoction. The content of II also decreased rapidly during the reflux in water. These results indicated that these small availabilities cause not only by volatilization but also by decomposition.