Shi Chang Pu (Acorus tatarinowii, Stone Calamus) is the dried rhizome of a perennial herb in the Araceae family, found growing in rocky stream crevices and marshy wetlands. Its persistent sharp aromatic fragrance is its most recognisable characteristic — and the chemical basis of its core TCM actions. The Shen Nong Ben Cao Jing classified it as an upper-class drug (shang yao) and summarised: “Pungent and warm. Governs Wind-Cold-Damp bi-syndrome, counterflow cough; opens the Heart orifice, supplements the five organs, opens the nine orifices, brightens the ears and eyes, produces the voice. Long-term use lightens the body and prolongs years.” Its pungent-warm aromatic nature gives it the ability to simultaneously open orifices (dispel Phlegm obstructing the Heart and clear orifices), resolve Damp (awaken the Spleen-Stomach from Damp-obstruction), and reach through channels from the Heart to the sensory orifices. Two thousand years of clinical application and modern pharmacological research both confirm its multi-target value across neurological, gastrointestinal, and ENT (ear-nose-throat) conditions.

I. Classical Records and TCM Properties

Three classical benchmarks:

• Shen Nong Ben Cao Jing: upper-class classification; establishes “open orifices, supplement five organs, open nine orifices, brighten ears and eyes” as core functions
• Ben Cao Gang Mu: extends applications to acute collapse (zhong e), febrile convulsions, epilepsy, and gynaecological haemorrhage
• Ben Cao Bei Yao: the most clinically precise classical summary — “Opens orifices and removes Phlegm; awakens Spleen and opens Stomach; sharpens hearing and brightens vision; treats forgetfulness, fright-epilepsy, tinnitus, and dysenteric inappetence”

TCM properties: Pungent-bitter, warm; enters Heart and Stomach channels. The pungent quality opens orifices and disperses Damp; the bitter quality dries Damp and dissolves Phlegm; the warm quality warms Yang, awakens the Spleen, and activates Qi through channels. The aromatic volatile quality is the key: fang xiang kai qiao (aromatic opens orifices) — the fragrance reaches where most herbs cannot, penetrating the closed orifices of the Heart and senses.

Appearance and identification: Flat cylindrical rhizome; many branches; 3–20cm long, 0.3–1cm diameter; surface brown, rough with dense nodes (internodes 0.2–0.8cm — the dense-node pattern distinguishes it from Water Calamus); hard, fibrous cross-section; white to pale red interior. Defining characteristic: “persistent sharp aromatic fragrance, bitter and mildly pungent taste.”

II. Four Core Actions

1. Open orifices and dissolve Phlegm — awaken consciousness (core action):
Shi Chang Pu’s aromatic pungent quality can break through the Phlegm-turbidity obstruction of the clear orifices (Heart orifice and sensory orifices). This is its defining classical action. Phlegm-Damp or Phlegm-Heat obstructing the Heart produces a spectrum from mild cognitive clouding (poor concentration, forgetfulness) to severe closed-orifice patterns (sudden unconsciousness, stroke aphasia, epileptic convulsions, febrile delirium). Shi Chang Pu enters the Heart channel specifically and penetrates this obstruction. The Ben Cao Bei Yao’s description “opens the Heart orifice” (kai xin qiao) captures this precisely: it opens the closed gate between consciousness and the world. Also suitable for daily Phlegm-Damp cognitive clouding — mental fatigue, foggy thinking, memory decline — particularly in the elderly and those engaged in sustained mental work.

2. Resolve Damp and awaken Spleen — harmonise the Middle Jiao:
The aromatic quality reaches the Spleen-Stomach: fang xiang xing pi (aromatic awakens the Spleen) is a key TCM principle, and Shi Chang Pu embodies it fully. When Damp-turbidity obstructs the Middle Jiao, it produces gastric and abdominal stuffiness and fullness, no desire to eat, nausea, and difficult bowel function. Shi Chang Pu dissolves this Damp-obstruction and restores the Spleen-Stomach’s ascending-descending transportation function. Its classical application for jin kou li (dysenteric inappetence — where severe dysentery produces complete inability to eat due to Damp-Heat obstructing Spleen-Stomach) demonstrates its capacity to restore Spleen function under severe Damp-Heat obstruction.

3. Sharpen hearing, brighten vision, and open the nine orifices:
The Shen Nong Ben Cao Jing records that Shi Chang Pu “opens the nine orifices, brightens ears and eyes, and produces the voice.” When Phlegm-Damp ascends to cloud the sensory orifices, it produces tinnitus, hearing reduction, blurred vision, and hoarse voice. Shi Chang Pu’s orifice-opening action reaches these sensory channels specifically, dissolving the Phlegm-Damp that obstructs them. Also opens the voice (treatment of hoarseness from Phlegm obstruction) — useful for those who overuse their voice professionally.

4. Dispel Wind and unblock channels — relieve bi-syndrome pain:
Pungent-warm and channel-penetrating, Shi Chang Pu can dispel Wind-Damp from channels and joints, providing adjunctive treatment for Wind-Cold-Damp bi-syndrome with joint stiffness, limb numbness, and pain. Used alongside dedicated Wind-Damp-dispelling herbs (Du Huo, Wei Ling Xian, Gui Zhi).

III. Four Classical Formulas

1. Di Tan Tang “Purge Phlegm Decoction” (Ji Sheng Fang)
Composition: Shi Chang Pu · Ban Xia · Tian Nan Xing · Chen Pi · Zhi Shi · Fu Ling · Ren Shen · Zhu Ru · Gan Cao. Action: purge Phlegm and open orifices, supplement Qi and strengthen Spleen. Indication: stroke with Phlegm-obstruction: sudden unconsciousness, aphasia, stiff tongue, mental clouding. The classic post-stroke formula when Phlegm-obstruction is the dominant mechanism.

2. Chang Pu Yu Jin Tang “Calamus-Turmeric Decoction” (Wen Bing Quan Shu)
Composition: Shi Chang Pu · Yu Jin · Zhi Zi · Lian Qiao · Zhu Ye · Zhu Li · Jiang Zhi. Action: clear Heat and dissolve Phlegm, open orifices and awaken Spirit. Indication: febrile illness with Phlegm-Heat internal obstruction: fever with delirious speech, mental clouding. When the obstruction is Heat-Phlegm rather than Cold-Phlegm, Yu Jin provides the clearing component while Shi Chang Pu opens the orifice.

3. Kai Jin San “Open Dysenteric-Inappetence Powder” (Yi Xue Xin Wu)
Composition: Shi Chang Pu · Huang Lian · Ren Shen · Shi Lian Zi · Fu Ling · Chen Pi · Dong Gua Ren. Action: clear Heat and resolve Damp, harmonise Stomach and open jin kou. Indication: dysenteric inappetence (jin kou li) — dysentery so severe the patient cannot eat; nausea and vomiting; abdominal distension and pain. Shi Chang Pu’s Spleen-awakening and Damp-resolving action restores the Spleen-Stomach’s capacity to receive food even under severe Damp-Heat obstruction.

4. Bu Wang San “Do-Not-Forget Powder” (Qian Jin Fang)
Composition: Shi Chang Pu · Yuan Zhi · Fu Ling · Ren Shen · Fu Shen. Action: supplement Heart and sharpen the mind, calm Spirit and prevent forgetting. Indication: forgetfulness, insomnia, palpitations, and multiple dreams. A classical longevity and cognitive-maintenance formula for the elderly and mentally active. The Shi Chang Pu-Yuan Zhi pairing is the formula’s core dyad: both enter the Heart, both open orifices and dissolve Phlegm, both reach the mind — together they amplify the cognitive-enhancement action beyond either herb alone.

IV. Three-Herb Differential: Shi Chang Pu, Shui Chang Pu, and Jiu Jie Chang Pu

V. Modern Pharmacology

Core chemical constituents: Volatile oil (the aromatic fraction): β-asarone, α-asarone, caryophyllene, and acoric ether. Also sterols, organic acids, and anthraquinones. The volatile oil is the pharmacologically active fraction responsible for the orifice-opening and CNS actions.

Documented pharmacological actions:

• Central nervous system: sedation, anti-convulsant action; improves learning and memory; neuroprotection; adjunctive benefit in dementia, neurasthenia, insomnia, and post-stroke cognitive impairment
• Gastrointestinal system: promotes digestive secretion; inhibits abnormal intestinal fermentation; relieves intestinal spasm; anti-ulcer action; suitable for chronic GI conditions
• Cardiovascular system: vasodilation; improved microcirculation; inhibits platelet aggregation; adjunctive lipid-lowering action
• Antimicrobial and anti-inflammatory: inhibits dermatophytes and common bacteria; anti-inflammatory and analgesic; external application for skin infections and pruritus
• Respiratory system: bronchodilation; antitussive; expectorant; adjunctive in bronchitis and asthma

Safety note on β-asarone: β-asarone has mild toxicity in animal studies at high doses. At standard clinical decoction doses (3–6g, not over-decocted), the concentration achieved is very low and considered safe. Avoid long-term high-dose use. The decoction process also metabolises some β-asarone, reducing its concentration further.

VI. Dosage and Safety

Internal dose: decoction 3–6g; fresh herb 6–12g; can be taken as pill or powder. Critical decoction note: do not decoct longer than 10–15 minutes — the volatile oil (the pharmacologically active fraction) evaporates with prolonged heat. Add at the end of the decoction when possible, or use low-boil brief extraction. This is one of the most important practical instructions for this herb.

External use: decoct and wash; or grind to powder and apply. For skin infections, pruritus, and carbuncles.

Contraindications:

• Yin deficiency with ascending Yang: night sweats, hot palms, dizziness, tinnitus, red tongue with scant coating — Shi Chang Pu’s pungent-warm aromatic-drying nature will further deplete Yin fluids and worsen ascending-Yang symptoms
• Irritability with profuse sweating, haemoptysis: warm-drying nature worsens these presentations; avoid
• Active exterior illness: using orifice-opening herbs during exterior-pathogen illness may “close the door with the pathogen inside” (bi men liu kou) — avoid until exterior illness resolves
• Pregnancy: pungent-warm penetrating nature may affect foetal Qi; use under specialist supervision only
• Overdose (>15g single dose): nausea, vomiting, dizziness; self-resolving after discontinuation; avoid exceeding recommended doses