Objective To study the characteristics of heart rate variabili ty (HRV) in states of calm supine position, supine position and counting, and ca lm upstanding position, and the relationship with TCM syndromes of cold-h eat and deficiency-excess. Methods Totally 233 patient s diagnosed by TCM & western medicine with different syndromes were divided into five groups. B y comparing the general changes of frequency domain of HRV under three kinds of condition s, the variation of HRV indexes was measured in the excess heat syndrome group ( 64 cases), deficiency cold syndrome group (16 cases), cold-heat complex syndrom e group (38 cases), yin deficiency with fire syndrome group (67 cases), and defic iency of both yin and yang syndrome group (48 cases). Results The low frequenc y (LF) and low frequency normalized unit (LFNU) manifested sympathetic nervous a ctivity were augmented and were related with the yang syndrome and heat syndrome obvi ously. The high frequency (HF) and high frequency normalized unit (HFNU) manifes ted parasympathetic nervous activity were augmented and were related with the yi n syn drome and cold syndrome. The increased LF/HF reflected the yang syndrome and hea t syndrome. The decreased LF/HF reflected yin syndrome and cold syndrome. The co ndition of counting had a weighing influence on the diagnosis of yang syndrome a nd heat syndrome. And the condition of upstanding played a weighing role in defi ciency syndrome and cold syndrome. Conclusion The law o f changes of HRV under three kinds of condition is helpful in syndrome differentiation of cold-heat an d deficiency-excess.

In order to explore the dose-response patterns of Gancao (Radix Glycyrrhizae) in Shanghan Lun (Treatise on Febrile Diseases), all prescriptions containing Gancao in Shanghan Lun were analyzed by frequency and hierarchical clustering analysis. The doses of Gancao used in Shanghan Lun ranged from six zhu (Chinese unit, and one zhu is equal to 0.65 g) to four liang (Chinese unit, and one liang is equal to 15.625 g). Doses of one, two, three or four liang were commonly used. One liang Gancao as juvantia was usually matched with Mahuang (Herba Ephedrae), Xingren (Semen Armeniacae) and Guizhi (Ramulus Cinnamomi) for restricting the excessive diaphoresis of Mahuang. Two liang Gancao was often matched with some couple drugs, such as Guizhi and Shaoyao (Radix Paeoniae), Shigao (Gypsum Fibrosum) and Zhimu (Rhizoma Anemarrhenae), Fuzi (Radix Aconiti Lateralis) and Ganjiang (Rhizoma Zingiberis), for warming yang to supplement qi, nourishing yin, detoxifying Fuzi, and preventing qi impairment from heat evil. Three liang Gancao was mainly matched with Banxia (Rhizoma Pinelliae) or Renshen (Radix Ginseng) for treating middle energizer emesis. Four liang Gancao was matched with Ganjiang or tonifying herbs for invigorating vital qi and relieving spasm in deficiency syndromes with contraction, palpitation or diarrhea. Gancao is used for treating many syndromes in Shanghan Lun. It is frequently used to treat excess or heat syndromes with one or two liang in a dose and deficiency or cold syndromes with three or four liang in a dose.