Shu Qi 蜀漆 — Chinese Herbal Medicine

Shu Qi (蜀漆) At a Glance

• Herb: Shu Qi
• Chinese name: 蜀漆 (Shu Qi)
• Latin name: Dichroae Folium
• Nature: Neutral
• Taste: Acrid, Bitter
• Meridian: Lung
• Category: Others

Shu Qi (蜀漆) refers to the dried leaves and young stems of Dichroa febrifuga Lour., a shrub native to the moist mountain valleys of Sichuan (古称蜀), from which its name derives. Closely allied to its root counterpart Chang Shan (常山), Shu Qi shares the same plant source but exerts a comparatively more vigorous action in the upper body, directing its force through the Lung to disperse phlegm and toxin. Classically regarded as one of the principal herbs for interrupting recurring malarial attacks, it occupies a narrow but decisive role in formulas targeting phlegm-toxin accumulation in the chest and diaphragm.

Actions & Therapeutic Effects

• Interrupts malaria and dispels malarial toxin — disrupts the cyclical pattern of alternating chills and fever caused by phlegm-toxin lodged in the shaoyang layer
• Expels phlegm and opens the chest — dislodges stubborn, congealed phlegm obstructing the Lung and diaphragm, relieving fullness and dyspnea
• Induces vomiting to expel pathogenic accumulation — its strong ascending, acrid nature drives upward to purge phlegm-food stagnation lodged in the upper jiao
• Disperses accumulations and softens masses — addresses abdominal glomus and concretions arising from phlegm and qi binding together
• Clears latent toxin — assists in resolving gu toxin and deep-seated pathogenic influences in classical usage

Clinical Applications in TCM

• Malarial disorders (nüè ji) with alternating fever and chills, especially recurring or chronic types — paired with Chang Shan and Cao Guo in formulas such as modified Jie Nüè Qi Bao Yin
• Phlegm obstruction in the chest and diaphragm causing fullness, oppression, and difficult breathing — combined with Ban Xia and Gua Lou
• Phlegm-food accumulation in the upper jiao where emesis is the desired therapeutic strategy — used with Zhi Zi as in classical emesis protocols derived from the Shang Han Lun tradition
• Abdominal masses and glomus (pi man) from phlegm-qi binding — used adjunctively with Bie Jia and Zhi Shi
• Gu toxin and stubborn latent pathogenic accumulation — referenced in classical formulas for intractable interior stagnation

Precautions & Safety

• Dosage: 3–6 g in decoction; stir-frying with wine (酒炒) or ginger juice moderates its emetic intensity and is the standard preparation for internal use
• Contraindicated in pregnancy; contraindicated in patients with deficiency of zheng qi, weak stomach, or tendency to vomit; use with caution in the elderly and debilitated
• Not for prolonged administration — febrifugine alkaloids are hepatotoxic with cumulative dosing; monitor liver function if extended use is clinically necessary
• Synergistic toxicity when combined with other emetic or harshly descending agents; avoid concurrent use with Lei Wan or Gua Di without specialist supervision

Classical TCM Formulas

• Shu Qi San (蜀漆散): Shu Qi, Yun Mu, Long Gu — for malaria (Nue Ji) with Phlegm-Heat. Source: Jin Gui Yao Lue.
• Chang Shan Yin (常山饮): Chang Shan (root) + Shu Qi + Chai Hu + Huang Qin — for malaria with alternating chills and fever. Source: Tai Ping Hui Min He Ji Ju Fang.
• Modern: febrifugine and halofuginone are studied as antifibrotic, anticancer, and antimalarial agents.

Herb Combinations

• Shu Qi (蜀漆) + Chang Shan (常山): the two Dichroa-derived antimalarials — Shu Qi is the young shoot, Chang Shan is the root; historically the core pair for malaria.
• Shu Qi (蜀漆) + Chai Hu (柴胡) + Huang Qin (黄芩): clears Shaoyang Heat and stops malarial paroxysms — the classical approach to intermittent fever.
• Shu Qi (蜀漆) + Yun Mu (云母) + Long Gu (龙骨): from Shu Qi San — treats malaria with Phlegm-Heat accumulation. Source: Jin Gui Yao Lue.
• Modern alternative: artemisinin-based combination therapies (ACTs) have largely replaced Shu Qi for malaria.

Pharmacology & Research

Antimalarial: febrifugine and isofebrifugine alkaloids inhibit Plasmodium falciparum prolyl-tRNA synthetase, disrupting parasite protein synthesis at nanomolar concentrations.
Emetic: febrifugine activates central and peripheral emetic pathways via vagal afferent stimulation, accounting for the classical vomiting-induction action.
Anti-inflammatory: dichroain and related quinazolinone alkaloids suppress NF-κB nuclear translocation, reducing IL-6 and TNF-α production in macrophage models.
Antipyretic: aqueous leaf extracts lower lipopolysaccharide-induced fever in rodent models, consistent with the classical cold-heat-resolving indication.
Hepatotoxic (adverse): febrifugine undergoes CYP3A4-mediated oxidative metabolism generating reactive intermediates that cause dose-dependent hepatocellular injury at supratherapeutic exposures.

Classical Descriptions

• “主疟及咳逆寒热，腹中癥坚痞结，积聚邪气蛊毒鬼疰。” — *Shennong Bencao Jing* (Divine Husbandman’s Classic of the Materia Medica, ca. 1st–2nd century CE): “Governs malaria, cough counterflow with alternating cold and heat, abdominal concretions, hard glomus, accumulations, evil qi, gu toxin, and ghost possession.”