Gua Lou (瓜蒌) — Trichosanthes Fruit | TCM Chest Bi & Phlegm-Heat Herb Guide

At a Glance

• Herb: Gua Lou
• Chinese name: 瓜蒌 (Guā Lóu)
• Latin name: Trichosanthes kirilowii Maxim.
• Nature: Cold
• Taste: Sweet / Bitter
• Meridian: Lung / Stomach / Large Intestine
• Category: Herbs that Clear Heat and Transform Phlegm
• Introduction: Gua Lou (瓜蒌), trichosanthes fruit (Trichosanthes kirilowii / T. rosthornii), is a multifaceted phlegm-resolving herb that simultaneously clears heat, transforms phlegm, loosens the chest, and moistens the intestines. Entering the Lung, Stomach, and Large Intestine channels, it is the premier herb for heat-phlegm obstructing the chest — particularly chest bi syndrome (胸痹) and lung abscess with thick, sticky yellow phlegm. All three parts are medicinal: the whole fruit (全瓜蒌) clears and transforms; the peel (瓜蒌皮) focuses on the chest; the seeds (瓜蒌仁/瓜蒌子) moisten intestines. Trichosanthin, derived from the root (天花粉), has been studied for anti-HIV and anti-tumor properties.

Action

• Clears heat and transforms phlegm (清热化痰): resolves thick, sticky yellow phlegm from lung heat — productive cough with difficult expectoration.
• Loosens the chest and dissipates nodules (宽胸散结): the key herb for chest bi syndrome — oppression, pain, and tightness from phlegm-heat obstructing the chest.
• Moistens and lubricates the intestines (润肠通便): seeds especially — treats constipation from heat-dryness injuring intestinal fluids.
• Reduces swelling and expels pus (消肿排脓): treats pulmonary and breast abscesses.

Clinical Application

• Chest bi syndrome (胸痹): angina, coronary artery disease with chest fullness, pain, and shortness of breath from phlegm-heat — classic with Xie Bai.
• Lung heat cough: productive cough with thick yellow phlegm, fever, chest pain.
• Lung abscess: combines with Yu Xing Cao, Jie Geng, Yi Yi Ren.
• Breast abscess and nodules: phlegm-heat mastitis — with Pu Gong Ying, Zhe Bei Mu.
• Constipation: heat-dryness type with dry, hard stools — seeds (瓜蒌仁) preferred.
• Diabetes: Tian Hua Fen (root) generates fluids and relieves thirst in消渴 pattern.

Precautions

• Spleen deficiency with cold-damp: avoid — cold, moistening nature worsens loose stools and cold-phlegm conditions.
• Incompatibility: traditionally incompatible with Wu Tou (附子 class herbs) — classical 十八反 (eighteen incompatibilities).
• Diarrhea: the seed’s laxative action may cause loose stools — use peel alone if needed.
• Parts used: Gua Lou Pi (皮) — chest and phlegm focus; Gua Lou Ren/Zi (仁/子) — intestinal moistening and phlegm; Quan Gua Lou (全) — combined action.
• Standard dose: 9–15g whole fruit or peel; 9–15g seeds; crush seeds before decocting.

Formula

• 瓜蒌薤白白酒汤 (Gua Lou Xie Bai Bai Jiu Tang): Gua Lou + Xie Bai + rice wine — the foundational chest bi formula from《金匮要略》; transforms phlegm and opens the chest.
• 小陷胸汤 (Xiao Xian Xiong Tang): Gua Lou + Huang Lian + Ban Xia — phlegm-heat in the chest with fullness, pain on pressure, and sticky yellow sputum.
• 清气化痰丸 (Qing Qi Hua Tan Wan): Gua Lou + Dan Nan Xing + Huang Qin — lung heat phlegm cough with thick yellow sputum and chest pain.
• 柴胡陷胸汤 (Chai Hu Xian Xiong Tang): Gua Lou + Chai Hu + Huang Lian — Shaoyang with phlegm-heat chest fullness.

Combinations

• For phlegm-heat obstructing the chest with chest pain: combine with Xie Bai, Ban Xia (Gua Lou Xie Bai Ban Xia Tang).
• For lung heat with thick yellow sputum: combine with Huang Qin, Zhi Mu, Sang Bai Pi.
• For breast abscess (mastitis): combine with Pu Gong Ying, Jin Yin Hua, Ru Xiang.
• For intestinal dryness constipation: use Gua Lou Ren (seeds) with Fire Hemp Seed, Yu Li Ren.
• For lung abscess: combine with Yu Xing Cao, Dong Gua Ren, Tao Ren.
• For coronary artery disease with chest pain: combine with Xie Bai, Dan Shen, Chuan Xiong.
• For diabetes with thirst: use Tian Hua Fen (root) with Mai Dong, Ge Gen.

Pharmacological Effects

• Expectorant
  • loosens and expels viscous phlegm from respiratory tract
• Antiplatelet
  • inhibits platelet aggregation, improves coronary circulation
• Antibacterial
  • active against Staphylococcus aureus, Streptococcus, E. coli
• trichosanthin (from root)
  • Antitumor: induces apoptosis in cancer cells
• Anti-inflammatory
  • reduces NF-κB-driven inflammation in lungs and skin
• dilates coronary arteries
  • Cardioprotective: reduces ischemic injury

Classic Description

• Shen Nong Ben Cao Jing (《神农本草经》): ‘Governs wasting-thirst, body heat with vexation and fullness, great heat, supplements deficiency and calms the center, and continues severed injuries.’
• Ben Cao Gang Mu (《本草纲目》): ‘Moistens Lung dryness, descends fire, treats cough, flushes phlegm binding, benefits the throat, stops wasting-thirst, facilitates the Large Intestine, and dissolves carbuncle swelling and sore toxin.’
• Ben Cao Jing Shu (《本草经疏》): ‘Trichosanthes Fruit is sweet in flavor, cold in qi, non-toxic; sweetness can supplement the Lung, moisture can eliminate dryness — hence it governs wasting-thirst, body heat with vexation and fullness, great heat, and supplements deficiency and calms the center.’
• Yao Pin Hua Yi (《药品化义》): ‘Trichosanthes Seed is moist in substance and drying in qi; specializes in the Lung; bitter in flavor and descending in nature — excels at flushing heat-phlegm.’