Sang Ye (桑叶) — Mulberry Leaf TCM Herb | Wind-Heat, Eyes, Lung Dryness & Blood Sugar

At a Glance

• Herb: Sang Ye
• Chinese name: 桑叶 (Sāng Yè)
• Latin name: Folium Mori
• Nature: Cold
• Taste: Bitter / Sweet
• Meridian: Lung / Liver
• Category: Herbs that Release the Exterior — Acrid and Cool
• Introduction: Sang Ye (桑叶, Folium Mori) is the dried leaf of Morus alba L. (white mulberry), a deciduous tree cultivated throughout China primarily for silkworm rearing. The leaves — especially those harvested after the first frost (Shuang Sang Ye, 霜桑叶) — are considered the highest quality for medicinal use, as frost concentrates active compounds. First recorded in the Shennong Bencao Jing, Sang Ye sits at the intersection of exterior-releasing and Liver-cooling — it disperses wind-heat from the Lung, clears Liver heat and brightens the eyes, and cools Liver-Lung blood heat to stop bleeding. In the Wenbing school it became one of the two pillars of Sang Ju Yin (with Ju Hua), defining the gentle, aromatic approach to early wind-heat febrile disease.

Action

• Disperses wind-heat and clears the Lung: Treats early wind-heat febrile disease with fever, cough, dry throat, and headache. Cools Lung heat and moistens Lung dryness. 2. Clears Liver heat and brightens the eyes: Treats Liver heat or wind-heat affecting the eyes with red, swollen, painful, or itchy eyes and blurred vision. 3. Cools the blood and stops bleeding: Treats haemoptysis and epistaxis from Lung or Liver heat forcing blood upward. 4. Clears summer-heat: Used in Qing Luo Yin (清络饮) for mild summer-heat patterns.

Clinical Application

• Sang Ye is frequently combined with Ju Hua — they share Lung and Liver affinities and complement each other in Sang Ju Yin for wind-heat with cough. Sang Ye’s superior Lung-moistening action makes it more suitable for dry cough and Lung dryness patterns, while Ju Hua excels at brightening eyes and calming Liver yang. For Lung dryness cough from autumn dryness, Sang Ye combines with Xing Ren and Bei Sha Shen in Sang Xing Tang (桑杏汤). Honey-processed Sang Ye (Mi Zhi Sang Ye) is preferred for Lung dryness cough — honey enhances the moistening quality. Modern applications include diabetes (blood sugar lowering), hypertension, and eye conditions.

Precautions

• Frosted Sang Ye (Shuang Sang Ye, harvested after first frost) is strongest for medicinal use. Honey-processed Sang Ye (Mi Zhi Sang Ye) preferred for Lung dryness cough. Use with caution in patients taking alpha-glucosidase inhibitors (acarbose, miglitol) — additive hypoglycaemic effects. Avoid large doses in patients with cold-damp Spleen patterns and loose stools.

Formula

• Sang Ju Yin (桑菊饮): Sang Ye, Ju Hua, Bo He, Xing Ren, Lian Qiao, Jie Geng, Lu Gen, Gan Cao.
• Sang Xing Tang (桑杏汤): Sang Ye, Xing Ren, Bei Sha Shen, Zhe Bei Mu, Dan Dou Chi, Zhi Zi Pi, Li Pi.
• Qing Zao Jiu Fei Tang (清燥救肺汤): Sang Ye, Shi Gao, Ren Shen, Mai Dong, E Jiao, Huo Ma Ren, Xing Ren, Pi Pa Ye, Gan Cao.

Combinations

• Sang Ye + Ju Hua + Bo He + Xing Ren (Sang Ju Yin): Wind-heat with cough. Source: Systematic Differentiation of Warm Diseases (温病条辨).
• Sang Ye + Xing Ren + Bei Sha Shen + Zhe Bei Mu (Sang Xing Tang): Autumn dryness with dry cough and fever. Source: Systematic Differentiation of Warm Diseases (温病条辨).
• Sang Ye + Ling Yang Jiao + Gou Teng + Ju Hua (Ling Jiao Gou Teng Tang): Liver wind convulsions with high fever. Source: Revised Popular Guide (重订通俗伤寒论).
• Sang Ye + Ce Bai Ye + Sheng Di Huang: Haemoptysis and epistaxis from Lung-Liver heat. Source: Si Sheng Wan variations.
• Sang Ye + Gou Qi Zi + Jue Ming Zi: Eye conditions — red eyes, blurred vision, eye strain from Liver heat. Source: Classical eye formula tradition.

Pharmacological Effects

• DNJ
  • Anti-diabetic: inhibits intestinal alpha-glucosidase, reducing post-prandial blood glucose — multiple clinical trials confirm significant hypoglycaemic effects
  • Anti-diabetic: Sang Ye products are widely marketed for diabetes management in Japan and China
• GABA and rutin
  • Antihypertensive: reduce blood pressure via multiple mechanisms
• Rutin and quercetin
  • Antioxidant: provide strong free-radical scavenging activity
• Anti-atherosclerotic
  • Reduces LDL oxidation and cholesterol absorption
• Antibacterial
  • Active against Staphylococcus aureus and various respiratory pathogens
• Ecdysterone
  • Neuroprotective: protects neurons from glutamate excitotoxicity

Classic Description

• 《神农本草经》(Shennong Bencao Jing, circa 200 CE): ‘桑根白皮（桑叶附），味甘，寒。除寒热出汗，主伤中五劳六极羸瘦，崩中脉绝，补虚益气。’ (Mulberry root bark [with Sang Ye appended]: sweet flavour, cold. Eliminates cold-heat with sweating; governs internal injury, five taxations, six exhaustions, emaciation, flooding with severed pulse; supplements deficiency and benefits qi.)
• 《本草纲目》(Bencao Gangmu, 1596): ‘桑叶，乃手、足阳明之药，汁煎代茗，能止消渴。’ (Sang Ye is the herb for the Hand and Foot Yangming channels. Decocted juice drunk as tea can stop wasting-thirst [diabetes].)
• 《温病条辨》(Wenbing Tiaobian, 1798): ‘桑叶，苦甘寒，善散风热，清肺润燥，清肝明目，为温病初起之要药。’ (Sang Ye: bitter, sweet, cold. Excels at dispersing wind-heat, clearing the Lung and moistening dryness, clearing the Liver and brightening the eyes — essential herb at the onset of warm disease.)