Filed under General TCM
The Secrets of Dosage in Chinese Herbal Medicine
By Dr Greta Young Jie De
The question concerning the exact dosage of many frequently used Chinese herbs has remained a bone of contention. The fact that the optimum dosage of many herbs have been a subject of much debates. Traditionally during the Qing dynasty many famous Chinese medicine practitioners had a preference to use flowers instead of the root is that flowers are light and is more penetrating. Reading through the case studies of Ye Tian Shi and Xu Ling Tai, I have found that the dosage is very often omitted. Does this mean that the dosage of the herbs is not the key to an effective treatment strategy? On the contrary this has been traditionally a well-kept secret.
An example can be cited by a case study of a patient suffering from edema and was being treated by Chen Song Mu陈颂幕in the Qing dynasty. He was given Ma Huang Fu Zi Gan Cao Tang (Ma Huang 8 fen, Fu Zi 1 qian and Gan Cao 1.2 qian. It was not effective. Wu Ju Tong was then consulted to treat this patient. The diagnosis by Chen was correct which is yang deficiency with water retention and the selection of formula was also correct. Ma Huang is for releasing the exterior; Fu Zi to support the yang while Gan Cao is to harmonised the middle. The fact that this was not effective is because the dosage was incorrect. Wu Ju Tong’s prescription was: Ma Huang 2 liang; Shu Fu Zi 1.6 liang; Zhi Gan Cao 1.2 liang. The result was effective.
Another case study extracted from “Wu Ju Tong Yi An (Case Studies of Wu Ju Tong)” recorded Chen Yuan Sheng’s mother suffered from headache located at the vertex, cold extremities, coldness and pain in the chest with desire to vomit. She was given Wu Zhu Yu Tang and after the medication her vomiting worsened. Chen consulted his grand uncle Chen Ji Pu who regarded the diagnosis was correct. Instead of prescribing the full dose of Wu Zhu Yu Tang, he half the dosage and added Huang lian 1.5g to negate the hot and acrid property of Wu Zhu Yu. The patient’s vomiting was resolved after one pack of medication.
From the above two case studies it can be seen that even though the diagnosis was correct, more importantly the dosage had to be spot on.
In the past most of the Chinese medicine practitioners are fully conversant with the four qi and five flavours of the herb, the affiliated channel of each herb and therefore the correct dosage to achieve a satisfactory result had been through repeated trial and error. In 1984 many Chinese medicine specialists attended a conference in Cang Zhou to investigate Zhang Xi Chun’s academic theory by looking into the dosage of Zhang Xi Chun’s theory on the herbal dosage. For example, Shi Gao , the dosage can be from 2 liang to 4 liang. The Qing practitioner Yu Si Yu when treating epidemic warm disease characterised by fever, his prescription of Shi Gao may range from 40~120g.
Wan Dai Tang is a famous formula from “Fu Qing Zhu Ne Ke (Women Diseases according to Fu Qing Zhu)” for treatment of leucorrhoea. The actual formula is: Bai Zhu 1 liang (30g); Shan Yao 1 liang (30g) Bai Shao 5 qian (15g); Ren Shen 1 qian (3g); Che Qian Zi 1 qian (3g); Cang Zhu 3 qian (9g); Gan Cao 1 qian (3g); Chen Pi 6 fen (1.8g); Jing Jie 6 fen (1.8g) and Chai Hu 5 fen (1.5g). If the prescription dosage differs from this ratio, then the end result is not effective.
The following are selected herbs and the dosage:
Ai Ye: Indicated for warming the channel and stop bleeding, large dosage can damage the liver cells causing toxic hepatitis; 3~5g can stimulate the stomach qi; 8g can warm the channel and stop bleeding, moderate pain while a large dosage can cause gastro-intestinal inflammation.
Bing Lang: Indicated to move qi, reduce food stagnation, disinhibit water and the dosage is 6~15g but when used for killing worms the dosage needs to be 60~120g.
Zhe Bei Mu: Indicated for clearing lung heat, moisten lung dryness and transforming phlegm, the dosage is 9~15g but if used for relieving toxin and dispersing bind such as lung abscess and scrofula, the dosage needs to be 18~30g.
Ban Xia: Indicated for vomiting, and eliminating dampness the dosage is 10~15g; to calm the shen >30g; small dosage of 6g is to downbear counterflow and harmonise the stomach, medium dosage of 15g is to transform phlegm and dissipate bind while a large dosage of 30~60g should be Jiang Ban Xia ie with ginger starting from 30g to gradually increase to 60g, this is for sedating and calming the shen and pain relieving.
Bo He: In Xiao Yao San the dosage is a mere 3g to disperse the constrained liver qi while in Cang Er Zi San the dosage is 15g to outthrust wind heat and clearing the head.
Bai Zhu: The normal dosage is 10g to tonify the spleen and stop diarrhoea while a larger dosage of 30~60g can augment qi and move bowel.
Chuan Xiong: For exterior pattern characterised by headache the dosage should not exceed 4g; for hypertension characterised by liver yang headache, the dosage is 9~12g; for headache due to blood stasis, the dosage can be 30~40g.
With the Qing dynasty practitioner Wang Qing Ren’s famous formula Xue Fu Zhu Yu Tang for treatment of headache due to blood stasis, the dosage of Chuan Xiong is 15~30g. Chuan Xiong as a guide herb to Shao Yang is more effective than Chai Hu, the dosage is 5~6g.
Dang Gui: Its function is to tonify and invigorate blood indicated for blood deficiency with blood stasis. The small dosage is for tonification while a larger dosage is for blood invigorating. For example Dang Gui Bu Xue Tang, Huang Qi dosage is 30g while Dang Gui is a mere 6g. The modern application of Dang Gui is not to exceed 10g. In Gui Pi Tang, Ba Zhen Tang the dosage of Dang Gui is only 3g.
Chai Hu: Zhang Zhong Jing in Shang Han Lun the dosage of Chai Hu for both Da Chai Hu Tang and Xiao Chai Hu Tang is half a jin (112g) with each pack to be taken three times averaging 37g per medication. The most prevalent use of Chai Hu is more for releasing exterior. The normal dosage for lifting the yang qi is 2~5g indicated for non- ascending of the clear yang and turbidity yin not descending or the sinking of the middle qi. The dosage of 5~10g is indicated for dispersing constrained liver qi such as emotional distress and constrained liver qi characterised by chest and rib-side fullness and pain. A larger dose of 10~30g is used as an anti-pyretic to resolve fever.
Summary: It can be seen the significance of dosage on the overall treatment effect even though the diagnosis is correct and if the dosage is not correct the end result can be disappointing. （Ref: Zhu Bing Lin朱炳林： Reluctance to share the correct dosage 不传之秘在用量）
Compiled and Translated by Dr. Greta Young Jie De