Gua Di 瓜蒂 — Chinese Herbal Medicine

Gua Di (瓜蒂) At a Glance

• Herb: Gua Di
• Chinese name: 瓜蒂 (Gua Di)
• Latin name: Pedicellus Cucumeris Melo
• Nature: Cold
• Taste: Bitter
• Meridian: Lung
• Category: Clear the Heat/Dry Dampness

Gua Di is the dried pedicle of the muskmelon (Cucumis melo), a powerful herb in the Chinese Materia Medica used to drive out lodged phlegm, stagnant food, and damp-heat pathogens through its strong upward-expelling action. Its cold, bitter nature clears heat, dries dampness, and resolves jaundice while directing turbid accumulations outward from the upper burner. Classical physicians reserved Gua Di for urgent excess conditions, pairing it carefully in small doses to avoid injury to righteous qi.

Actions & Therapeutic Effects

• Induces vomiting to expel phlegm-rheum and retained food from the upper burner
• Clears heat and dries dampness
• Resolves damp-heat jaundice
• Opens the nasal passages and disperses turbid dampness (topical)
• Expels water accumulation and reduces edema

Clinical Applications in TCM

• Phlegm obstructing the chest and diaphragm with fullness and dyspnea: combine with Chi Xiao Dou in Gua Di San (《伤寒论》)
• Damp-heat jaundice with yellow sclera and dark urine: pair with Yin Chen Hao and Zhi Zi
• Retained food causing epigastric distension and foul belching: use alone as a powder washed down with warm water
• Turbid nasal discharge or nasal polyps from damp-heat: apply Gua Di powder topically to nasal passages
• Wind-phlegm lodging in the throat with rattling: combine with Zao Jiao (皂荚)
• Toxic substance ingestion requiring urgent evacuation: use as single-herb emetic preparation

Precautions & Safety

• Dosage: 2.5–5 g in decoction; 0.3–1 g as powder for direct ingestion; apply topically as needed for nasal conditions
• Contraindicated in qi or blood deficiency, weak constitution, pregnancy, active upper gastrointestinal bleeding, and esophageal disorders
• Discontinue immediately if vomiting becomes uncontrollable; excessive emesis can precipitate qi collapse

Classical TCM Formulas

• Gua Di San (瓜蒂散): Gua Di (powder) + Chi Xiao Dou (powder) taken with Dan Dou Chi decoction — induces vomiting for Phlegm-Food obstruction in the chest and diaphragm. Source: Shang Han Lun.
• Gua Di San (瓜蒂散) (Jin Gui Yao Lue version): Gua Di single herb — for Phlegm obstruction.
• Modern note: gastric lavage has replaced therapeutic emesis in modern clinical practice.

Herb Combinations

• Gua Di (瓜蒂) + Chi Xiao Dou (赤小豆): the classical emetic pair — Gua Di induces vomiting, Chi Xiao Dou drains downward. Source: Gua Di San (Shang Han Lun).
• Gua Di (瓜蒂) + Dan Dou Chi (淡豆豉): a milder emetic combination for Phlegm-Heat obstruction in the chest.
• Gua Di (瓜蒂) + Yu Jin (郁金): the bitter emetic pair for Phlegm-Heat misting the Heart with manic behaviour.
• Modern replacement: induced emesis is almost never clinically indicated in modern medicine; Gua Di is of historical interest primarily.

Pharmacology & Research

Cucurbitacins (B, D, E): primary emetic compounds; cytotoxic activity demonstrated against hepatocellular and colorectal cancer lines in vitro.
Sterols and triterpenoids: support diuretic and anti-edema effects consistent with classical water-expelling use.
Flavonoids: contribute anti-inflammatory and hepatoprotective activity supporting damp-heat jaundice applications.

Classical Descriptions

• “主大水，身面四肢浮腫，下水，殺蠱毒，咳逆上氣。” — Shennong Bencao Jing (神農本草經)