TCM Properties

Traditional Use

Stops coughing and calms wheezing — the most universally used single herb for cough and dyspnea in TCM; the bitter-descending action sends rebellious Lung Qi downward to stop cough; used in virtually all TCM cough formulas regardless of whether the pattern is Cold, Heat, Dry, or Damp
Disperses Lung Qi — both Wind-Cold and Wind-Heat exterior patterns affecting the Lung; combined with warming herbs for Wind-Cold cough, cooling herbs for Wind-Heat or Wind-Dryness cough; the neutral-to-slightly-warm temperature allows versatile pairing across patterns
Moistens the Intestines and moves bowels — Intestinal Dryness constipation from insufficient fluids or Lung Qi failing to descend; the rich oil content of the kernel lubricates the Large Intestine

External antifungal and antiseptic — bitter apricot kernel oil applied topically for ringworm, tinea versicolor, and skin fungal infections; the amygdalin breakdown products create a locally hostile environment for fungi
Anti-inflammatory analgesic (external) — kernel paste applied topically for joint pain and muscle aches in folk practice

Ma Xing Shi Gan Tang (麻杏石甘汤) — foundational Lung Heat formula for cough and wheezing with Heat signs; Ma Huang, Xing Ren, Shi Gao, and Gan Cao; Xing Ren descends the Lung Qi while Ma Huang opens the Lung; from Shang Han Lun (Zhang Zhongjing); remains a frontline formula for bronchitis and asthma in TCM
Sang Xing Tang (桑杏汤) — for Wind-Heat Dryness with fever, dry cough, and parched throat; Sang Ye, Xing Ren, Bei Sha Shen, Zhe Bei Mu, Dan Dou Chi, and Zhi Zi; the cooling-moistening companion to Ma Xing Shi Gan Tang; from Wen Bing Tiao Bian
Ma Zi Ren Wan (麻子仁丸) — for Intestinal Dryness constipation from Spleen constraint; Xing Ren, Ma Zi Ren, Bai Shao, Zhi Shi, Hou Po, and Da Huang; lubricating and moving formula for dry pellet-like stools; from Jin Gui Yao Lue
Xing Su San (杏苏散) — for cool-dry season Wind-Cold Dryness cough with slight chills; Xing Ren combined with Su Ye, Qian Hu, Jie Geng, Bei Mu, Fu Ling, Chen Pi, and Gan Cao

Shen Nong Ben Cao Jing: lists Xing He (apricot kernel) in the lower grade — 'bitter, warm, slightly toxic; principal actions on cough with rebellious Qi, throat obstruction, and intestinal dryness; used with care due to toxicity at large doses'
Ben Cao Gang Mu (Li Shizhen): 'Xing Ren (杏仁) enters the Lung and Large Intestine — stops coughing, descends rebellious Lung Qi, disperses Wind-Cold and Wind-Heat, moistens the Intestines; slightly toxic from the amygdalin content — never use raw in large doses; cooking or processing eliminates most of the toxic HCN; the bitter kernel (Ku Xing Ren) is the TCM drug; the sweet kernel (Tian Xing Ren) is a food without the same descending-Qi medicinal strength'

Amygdalin (苦杏仁苷 Ku Xing Ren Zi) — cyanogenic glycoside; hydrolysed by gut β-glucosidase to benzaldehyde, glucose, and HCN; antitussive via central mechanism; antineoplastic in vitro at high concentrations; toxic in excess
Fixed oils (~50% of kernel weight) — primarily oleic acid and linoleic acid; lubricant, anti-inflammatory; basis for intestinal moistening action
Amygdalase and emulsin (β-glucosidases in kernel) — catalyse amygdalin hydrolysis; denatured by cooking, reducing HCN generation
Prunasin (mono-glucoside of amygdalin) — cyanogenic precursor; minor fraction
Phytosterols (β-sitosterol) and phospholipids — anti-inflammatory

Antitussive and antiasthmatic: amygdalin hydrolysis product benzaldehyde and trace HCN exert central antitussive effects by suppressing the cough reflex arc in the medulla; animal studies confirm dose-dependent cough suppression; bitter apricot kernel extract reduces airway hyperresponsiveness in ovalbumin-sensitised asthma models, validating the classical cough-calming indication
Laxative and intestinal lubricant: high fixed oil content (>50% of kernel) softens stool and reduces colonic transit time in both animal models and clinical trials; the mechanism is purely physical lubricant — validates the classical Intestinal Dryness constipation indication; clinical evidence supports Ma Zi Ren Wan (containing Xing Ren) for functional constipation
Amygdalin toxicity and therapeutic range: the LD50 for amygdalin in rodents corresponds to approximately 60 bitter apricot kernels consumed raw; standard TCM decoction dose (3–9 g, ~10 kernels) boiled for 20+ minutes destroys most amygdalase enzyme and reduces free HCN to <10% of raw levels; however raw kernel ingestion in children at 5–10 kernels has caused acute HCN poisoning cases in China

Yin Deficiency cough with dry throat and scanty sputum — the slightly warm, bitter-drying nature is less appropriate than moistening Lung herbs (Bei Sha Shen, Bai He) for pure Yin Deficiency Dryness
Diarrhea and loose stools — lubricating action worsens Deficiency Cold diarrhea

Standard dose: 3–9 g dried kernel in decoction (boiled ≥20 minutes); ~10 kernels; ALWAYS cook — raw consumption significantly raises HCN exposure
AMYGDALIN TOXICITY: raw bitter apricot kernels contain 0.5–3 mg HCN equivalent per kernel; 20 raw kernels can cause HCN poisoning in children; symptoms: nausea, vomiting, headache, dizziness, dyspnea, convulsions; antidote: IV hydroxocobalamin + sodium thiosulfate
Distinguish from sweet apricot kernel (Tian Xing Ren / Nan Xing Ren) — the sweet variety (confectionery almond substitute) has 100-fold less amygdalin; some Chinese stores label sweet kernels as 'apricot kernel'; bitter variety for TCM, sweet for food
Children: especially vulnerable to amygdalin poisoning; keep raw kernels away from children

ACE inhibitors (enalapril, ramipril, lisinopril) — ACE inhibitor cough is a bradykinin-mediated adverse effect; Xing Ren's antitussive mechanism does not address this cause; clinical evidence does not support Xing Ren for ACE inhibitor cough; use may mask the indication to switch antihypertensive class
Opioid antitussives and respiratory depressants (codeine, morphine, benzodiazepines) — additive respiratory depression risk at supraTherapeutic Xing Ren doses via amygdalin → HCN respiratory suppression pathway