Gegen Tang (Pueraria Decoction) for Hypertension Is Worth Exploring

Yesterday, reading a medical book, I came across a case in the Du Wenxiao Yi'an (Medical Cases of Du Wenxiao) in which Dr. Du Wenxiao treated a high-risk hypertension patient.

The patient, Yan, 51 years old, had had hypertension for over 10 years. Four days earlier, he suddenly developed dizziness, palpitations, insomnia, cold hands and feet, limb numbness, and fright and palpitations. On hospital examination, blood pressure was 250/105 mmHg, with both diastolic and systolic pressure too high. TCM herbs that pacified liver and extinguished wind, cleared heat and nourished yin, and soothed the liver and downborne counterflow were used for four days without effect; Western vasodilators and antihypertensives were also ineffective. He was emotionally tense, his headache worsened, and he could not sleep all night.

Dr. Du saw that the patient had a bluish-yellow complexion, slightly trembling hands, numb fingertips, a thin white tongue coating, and icy hands and feet; even under thick quilts he still felt cold and wind-averse, with no sweating and clear abundant urine. Recalling that the previous herbs that pacified liver and extinguished wind, cleared heat and nourished yin, and soothed the liver and downborne counterflow had failed, Dr. Du considered the patient to have Taiyang disease among the six meridians, matching some of the medication indications for Gegen Tang. He therefore decided to treat with modified Gegen Tang. The prescription was: Gegen (Pueraria) 30 g, Guizhi (cinnamon twig) 12 g, Mahuang (ephedra) 12 g, Baishao (white peony) 15 g, prepared Fuzi (processed aconite) 30 g (decocted first), Gancao (licorice) 6 g, fresh ginger 3 slices, red dates 30 g. Decoct in water and take; all Western medicines were stopped.

The next day the patient's symptoms markedly improved, and blood pressure dropped to 180/95 mmHg. Aconite was then removed and the original Gegen Tang was continued for another 2 doses; all symptoms resolved, blood pressure dropped to 160/90 mmHg, and he returned to work. Follow-up for three months showed no recurrence.

This case interested me greatly, because I myself had previously used Gegen Tang to treat one hypertension patient. That patient was a family member of a cancer patient; when accompanying his relative to see me for cancer treatment, he begged me to help treat his years-long cervical spondylosis. This patient had long worked as a driver; due to his occupation, his neck had been stiff and painful for years, and he was averse to wind and cold, without sweating even in midsummer. I treated him with the original Gegen Tang formula, and after taking it, his cervical spondylosis symptoms greatly improved. Not only that, his years-long hypertension was also resolved along with it, and he has had no hypertension problem since.

How can Gegen Tang treat hypertension? This is truly puzzling, especially since Gegen Tang contains ephedra. According to modern pharmacological experiments, ephedra has the side effect of raising blood pressure, and hypertension patients should avoid ephedra. If we judge solely from the modern pharmacology perspective, we would not dare to give any ephedra-containing formula to hypertension patients. But both Dr. Du's treatment and mine achieved blood-pressure-lowering effects. So when choosing TCM formulas for patients, we should indeed refer to modern pharmacological research, but we must not be completely bound by it; rather, we should value TCM's principle of treatment based on pattern differentiation even more.

Hypertension is divided into primary and secondary hypertension. Among secondary hypertension, renal hypertension and hypertension caused by aortitis may both be somewhat similar to the indications for Gegen Tang in TCM.

Renal hypertension is mainly caused by renal disease leading to water retention and increased extracellular volume, as well as renal RAAS activation and reduced natriuretic hormones. The causes of aortitis are complex; immune dysfunction after infection (streptococcus, Mycobacterium tuberculosis, viruses, etc.) and cytokine inflammatory responses trigger aortitis, which in turn causes secondary hypertension. Both of these diseases commonly present with neck-back discomfort, cold aversion with cold limbs, and no sweating with scant urine—precisely the TCM indications for Gegen Tang. So it is not strange that Gegen Tang can treat hypertension.

The Japanese Kampo physician Sugiyama Waichi (Tang Ben Qiu Zhen) proposed in his book Kōkan Igaku (Imperial Chinese Medicine) that people fall ill because hereditary factors or irregular daily life and diet cause the stagnation of three poisons—food, water, and blood—resulting in autointoxication. This view inherited the idea of another Japanese Kampo physician, Yoshimasu Tōdō, that “all diseases are but one poison,” and refined it further.

From the modern medical perspective, part of secondary hypertension is caused by water retention of various kinds; this water retention raising blood pressure is strikingly similar to the water poison causing disease described by Sugiyama Waichi. Most Western antihypertensive drugs also act by diuresis to lower pressure. Primary hypertension has an unclear cause, and whether Gegen Tang can treat primary hypertension is still worth studying, but it is an undeniable fact that the water-retention problem in some secondary hypertension can indeed be solved with Gegen Tang.

From this we can even speculate that other TCM formulas that promote sweating and diuresis also have blood-pressure-lowering effects. Moreover, for some secondary hypertension patients, this treatment can even achieve a radical cure. Once the right formula is found for a patient, the hypertension problem can be solved once and for all, without requiring the patient to take antihypertensive drugs for life.

When using Gegen Tang to treat hypertension, the patient should meet the following clinical features: 1. no sweating with cold aversion; 2. neck-back discomfort with limb numbness; 3. clear urine. Because Gegen Tang is an acrid-wind exterior-releasing formula treating wind-cold exterior syndrome, no sweating with cold aversion characterizes wind-cold syndrome, neck-back discomfort is Gegen Tang's unique feature, and clear urine indicates the wind-cold has not yet transformed into heat, so using acrid-warm exterior-releasing formulas will not cause major side effects. If these features are not met, Gegen Tang should not be given to hypertension patients.