1. Formula Background & Records
Bi Xie Shen Shi Tang (萆薢渗湿汤), or Tokoro Decoction to Drain Dampness, is a classical Qing-dynasty formula from Gao Bingjun’s Yang Ke Xin De Ji (Collected Experiences in Sore and Ulcer Medicine). It belongs to the category of formulas that clear Damp-Heat from the Lower Burner and drain turbidity through the urine.
This formula addresses Damp-Heat pouring downward into the skin and channels of the lower body, a common pattern of weeping eczema, lower-leg ulcers (lian chuang), and hot swollen legs. Typical signs include red, oozing, or itchy eruptions on the lower limbs, heavy aching legs, dark scanty urine, a red tongue with yellow greasy coating, and a slippery rapid pulse. Combining Bi Xie as the chief herb to separate the clear from the turbid and drain Dampness, Yi Yi Ren, Ze Xie, Chi Fu Ling, Hua Shi, and Tong Cao to leach Damp-Heat through urination, Huang Bai to dry Damp-Heat in the Lower Jiao, and Mu Dan Pi to cool and invigorate Blood so Heat does not scorch the skin, Bi Xie Shen Shi Tang guides downward Damp-Heat out through the urine and is distinct from Bi Xie Fen Qing Yin, which treats cloudy urine from deficiency rather than excess Damp-Heat sores.
2. Clinical Applications in Dermatology
Bi Xie Shen Shi Tang (Dioscorea Decoction to Percolate Dampness) is frequently used for skin conditions driven by trapped damp-heat:
-
Acute Eczema: If a patient presents with red, flushed rashes, dense blisters, severe itching, and weeping sores—often accompanied by dry stools, dark urine, and a red tongue with a yellow, greasy coating—this formula is a go-to choice. Generally, after a short course (3 to 5 doses), patients often see reduced weeping, eased itching, and fading rashes.
-
Seborrheic Dermatitis: For symptoms like a highly greasy scalp, itchiness, redness, and flaking skin, this formula helps regulate sebum (oil) production and calm the skin by clearing out the underlying damp-heat.
3. Clinical Applications in Urology
Because the formula excels at clearing the lower body, it is highly effective for urinary tract issues:
-
Acute Cystitis (Bladder Inflammation): Commonly used when a patient experiences frequent, urgent, burning, or painful urination. Other signs might include a bitter taste in the mouth, dry mouth, and a rapid pulse. The formula helps flush out the irritation and restore normal urination.
-
Urethritis: For patients with sharp, burning pain in the urethra, localized redness and swelling, or slight discharge, this formula works by cooling the heat, draining the dampness, and effectively clearing the local inflammation.

4. Clinical Applications in Other Diseases
Trapped damp-heat can settle in other areas of the lower body, and this formula can be adapted to help:
-
Joint Pain: When damp-heat pours downward into the lower limbs, it can cause swollen, painful, and stiff joints. The formula helps by clearing the heat, draining the fluid buildup, and unblocking the energy channels (meridians) to relieve pain.
-
Scrotal Eczema: For localized symptoms like severe itching, dampness, redness, and swelling in the scrotal area, using this formula can effectively dry the dampness, calm the irritation, and promote healing of the delicate skin.