Peng'e San for Sudden Obstruction of Urination (Acute Urinary Retention)
The "Jijia Puji Fang" records a formula named "Peng'e San." Its composition is: Peng'ezhu (i.e., Ezhu, Zedoaria), Huixiang (Fennel), and Shengcha (i.e., unroasted green tea) in equal parts. Grind the above together into a fine powder. Take 2 qian (6g) each time, with one large bowl (300ml) of water, 2 qian (6g) of salt, and 2 cun (6.6cm) of scallion white, decoct together down to two-thirds of a bowl (200ml). Take warm on an empty stomach, dregs and all.
This formula warms the interior and dispels cold, transforms qi and promotes urination. It treats "sudden obstruction of urination," i.e., acute urinary retention. This symptom is mostly caused by conditions such as benign prostatic hyperplasia or hypertrophy, prostatitis, prostate cancer, bladder cancer, or acute urinary tract infection in middle-aged and elderly men, and is especially common in middle-aged and elderly men with prostatic hypertrophy.
Ezhu in this formula is the rhizome of Curcuma phaeocaulis or Curcuma kwangsiensis (Zingiberaceae). TCM holds that Ezhu moves qi, breaks blood, disperses accumulation, and relieves pain. Modern pharmacological research shows Ezhu has anticoagulant, anti-platelet-aggregation, anti-tumor, anti-fibrotic, analgesic, anti-inflammatory, and antibacterial effects. Ezhu is a commonly used TCM herb for benign and malignant tumors and hyperplastic tissue diseases. Building a formula mainly around Ezhu treats the root cause of conditions such as benign prostatic hyperplasia and prostatic hypertrophy.
The Huixiang in this formula is the seed of Foeniculum vulgare (Umbelliferae); it is carminative and expectorant, dispels cold, strengthens the stomach, and relieves pain. Fennel bidirectionally regulates urination: when urination is frequent it improves frequency and reduces the number of voids, and when urination is blocked it promotes urination. Prostate disease often causes either frequent urination or urinary retention, or alternation between the two; fennel treats these symptoms well.
The raw tea and scallion white in this formula are everyday drinks or foodstuffs. Unroasted green tea has a strong diuretic effect, mainly because of the caffeine it contains. Like fennel, scallion white also bidirectionally regulates urination: when urination is blocked it promotes diuresis, and when urination is frequent it reduces the number of voids. Adding salt has two functions: it regulates body-fluid metabolism and helps reduce inflammation and swelling.
In sum, this formula is rationally composed. Although the herbs are simple, it genuinely treats sudden obstruction of urination (acute urinary retention) and may be used as a diuretic.