补心脾，润肝肾
辛甘而润。其气清香，能透心肾而悦脾（昂按∶凡补脾药多燥，此润药而香能舒脾，燥
脾药中兼用最良）。养心气，润肾燥，助脾滋肝（王好古曰∶肝经气分药），益智宁神（养心）
，聪耳明目（甘益血，香通窍），益血止汗（心生血，汗为心液），除风湿。愈惊痫，泽皮肤，
辟鬼魅。
炒研去油，油透者勿用。畏菊花。
补阴，凉血
苦涩微寒（《本草》微温）。养阴滋肺而燥土最清血分，为补阴要药。
止吐衄崩淋，肠风尿（血）痢（血），一切血证，去冷风湿痹，历节风痛（肢节大痛，
昼静
夜剧，名白虎历节风。亦风寒湿所致）。涂汤火伤（捣烂水调涂），生肌杀虫，炙罨冻疮，汁
乌髭发。
取侧者（丹溪曰∶多得月令之气，随月建方取），或炒或生用。桂、牡蛎为使。恶菊花。
宜酒（万木皆向阳，柏独四指，受金之正气，坚劲不凋，多寿之木，故元旦饮椒柏酒以辟邪）
。
大燥，补肾命火
辛甘大热，气浓纯阳。入肝、肾血分（平肝、补肾），补命门相火之不足（两肾中间，
先天祖气，乃真火也。人非此火，不能有生，无此真阳之火，则无以蒸糟粕而化精微，脾胃
衰败，气尽而亡矣），益阳消阴。治痼冷沉寒，能发汗疏通血脉，宣导百药（辛则善散，热
则通行）。去营卫风寒，表虚自汗（阳虚），腹中冷痛，咳逆结气（咳逆亦由气不归元，桂能
引火，归宿丹田）。
木得桂而枯（削桂钉木根，其木即死），又能抑肝风而扶脾土（肝木盛则克土，辛散肝
风，甘益脾土），从治目赤肿痛（以热攻热，名曰从治），及脾虚恶食（命火不足），湿盛泄
泻（土为木克，不能防水。古行水方中，亦多用桂，如五苓散、滋肾丸之类），补劳明目，
通经堕胎（辛热能动血故也）。
出岭南桂州者良（州因桂名）。色紫肉浓，味辛甘者，为肉桂（入肝、肾、命门）。去粗
皮用（其毒在皮），去里外皮，当中心者，为桂心（入心），枝上嫩皮，为桂枝（入肺、膀胱
及手足）。得人参、甘草、麦冬良。忌生葱、石脂（本草有菌桂、筒桂、牡桂、版桂之殊。
今用者亦罕分别，惟以肉浓气香者良）。
补益心脾，滋润肝肾。
气味辛甘而滋润。其香气清透，能通达心肾并愉悦脾气（汪昂按：凡是补脾的药物大多性燥，此药虽润但香气能舒展脾气，在燥性补脾药中兼用最为适宜）。滋养心气，滋润肾燥，辅助脾脏并滋养肝脏（王好古说：这是调理肝经气分的药物），益智安神（通过养心实现），聪耳明目（甘味有益血液，香气能通利孔窍），补血止汗（心脏生成血液，汗液是心的外液），祛除风湿。治愈惊痫，润泽皮肤，辟除邪祟。
需炒制后研磨，去除油脂，若油分渗出者不可使用。忌与菊花同用。
补阴，凉血。
味道苦涩，性质微寒（《本草》记载为微温）。滋养阴液、滋润肺脏并燥湿，最善于清除血分热毒，是补阴的重要药物。
止血吐、鼻衄、崩漏、淋证，以及肠风便血、尿血痢疾等一切出血病症；驱散因寒冷引起的风湿痹痛和历节风痛（肢体关节剧烈疼痛，白天安静夜间加重，称为白虎历节风，也是由风寒湿邪所致）；外用可治疗汤火烫伤（捣烂后用水调匀涂抹），促进生肌杀虫；炙烤后敷贴可治冻疮；汁液可使胡须头发变黑。
选取侧生的枝条（朱丹溪说：多得月令之气，随月份变化采集），或炒用或生用。桂枝、牡蛎为其引经药。忌与菊花同用。
宜用酒送服（万物皆向阳生长，唯有柏树树枝四指方向伸展，承受金的正气，坚硬强劲不凋谢，是多寿之木，所以元旦饮用椒柏酒以辟邪）。
大燥，补肾命门之火。
气味辛甘大热，气浓纯阳。入肝、肾血分（平抑肝气、补肾），补益命门相火的不足（两肾之间，先天祖气，即真火。人如果没有此火，就不能生存，没有此真阳之火，就无法蒸化糟粕转化为精微物质，导致脾胃衰败，气尽而亡），益阳消阴。治疗顽固的冷积沉寒，能发汗疏通血脉，引导百药（辛味善于发散，热性能通行）。祛除营卫间的风寒，治疗表虚自汗（阳虚所致），腹中冷痛，咳逆结气（咳逆也是因为气不归元，肉桂能引火归元至丹田）。
树木遇到肉桂就会枯死（削下肉桂钉入树根，树木即死），又能抑制肝风并扶持脾土（肝木过盛会克制脾土，辛味疏散肝风，甘味补益脾土），采用从治法治疗目赤肿痛（以热攻热，称为从治），以及脾虚食欲不振（命门火不足）、湿气过重导致的泄泻（脾土被肝木克制，不能制约水湿。古代利水方剂中，也多用肉桂，如五苓散、滋肾丸之类），补虚劳明目，通经堕胎（因为辛热能动血）。
产自岭南桂州的品质优良（州名因桂而得名）。颜色紫红、肉质厚、味道辛甘的，称为肉桂（入肝、肾、命门）。去掉粗皮使用（毒性主要在皮中），去掉内外层皮，取中心部分，称为桂心（入心）；枝条上的嫩皮，称为桂枝（入肺、膀胱及手足经脉）。与人参、甘草、麦冬配伍效果良好。忌与生葱、赤石脂同用（《本草》中有菌桂、筒桂、牡桂、板桂的区别。现在使用的也很少分别，只以肉质厚、香气浓的为佳）。
Tonifies the Heart and Spleen, moistens the Liver and Kidneys.
Pungent, sweet, and moistening in nature. Its aroma is clear and penetrating, capable of reaching the Heart and Kidneys while soothing the Spleen (Wang Ang notes: Most herbs that tonify the Spleen are drying; this herb is moistening yet its fragrance can soothe the Spleen, making it an excellent adjunct to drying Spleen-tonifying herbs). Nourishes Heart Qi, moistens Kidney dryness, assists the Spleen and nourishes the Liver (Wang Haogu states: It is a herb for regulating Qi in the Liver channel), enhances wisdom and calms the Spirit (by nourishing the Heart), sharpens hearing and vision (Sweetness benefits Blood, fragrance opens orifices), benefits Blood and stops sweating (The Heart generates Blood, sweat is the fluid of the Heart), dispels Wind-Damp. Cures epilepsy and convulsions, moisturizes the skin, wards off evil influences.
Stir-fry and grind, removing the oil; do not use if the oil has seeped out. Averse to Chrysanthemum Flower (Juhua).
Nourishes Yin, cools Blood.
Bitter, astringent, slightly cold (Bencao records it as slightly warm). Nourishes Yin, moistens the Lungs, and dries Dampness; it is particularly effective at clearing Heat from the Blood level, serving as a key herb for nourishing Yin.
Stops hematemesis, epistaxis, metrorrhagia, strangury, intestinal wind with bloody stool, and dysentery with blood; treats all types of bleeding disorders; expels Cold-induced Wind-Damp Bi syndrome and Li Jie Feng pain (severe joint pain, quiet during the day and worse at night, known as White Tiger Li Jie Feng, also caused by Wind-Cold-Damp); applied externally for burns and scalds (mash and mix with water for application), promotes tissue regeneration and kills parasites; roasted and applied for frostbite; juice darkens beard and hair.
Select branches growing on the side (Zhu Danxi says: They obtain the Qi of the lunar months, so harvest according to the month's construction), stir-fried or used raw. Cassia Twig (Guizhi) and Oyster Shell (Muli) act as guides. Averse to Chrysanthemum Flower (Juhua).
Best taken with wine (All plants turn towards the sun, but Cypress branches extend in four directions, receiving the righteous Qi of Metal, remaining firm and unyielding, symbolizing longevity; thus, drinking Pepper and Cypress wine on New Year's Day wards off evil).
Extremely drying, tonifies Mingmen Fire.
Pungent, sweet, and extremely hot, with a dense, purely Yang Qi. Enters the Blood levels of the Liver and Kidneys (calms the Liver, tonifies the Kidney), supplements the deficiency of Mingmen Minister Fire (located between the two kidneys, the ancestral Qi of congenital origin, which is True Fire. Without this Fire, life cannot exist; without this True Yang Fire, one cannot steam and transform waste into essence, leading to Spleen-Stomach failure, exhaustion of Qi, and death), benefits Yang and eliminates Yin. Treats entrenched Cold and deep-seated Chill, induces sweating, unblocks collaterals, and guides other herbs (Pungency disperses well, heat promotes circulation). Expels Wind-Cold from Ying and Wei levels, treats spontaneous sweating due to exterior deficiency (Yang deficiency), cold pain in the abdomen, rebellious Qi with cough and chest tightness (Rebellious Qi also stems from Qi failing to return to its root; Cassia can guide Fire back to the Lower Dantian).
Wood withers when exposed to Cassia (if Cassia chips are nailed into tree roots, the tree dies); it can also suppress Liver Wind and support Spleen Earth (Excessive Liver Wood overacts on Earth; pungency disperses Liver Wind, sweetness tonifies Spleen Earth), employs contrary treatment for red, swollen, and painful eyes (using heat to attack heat, called contrary treatment), and addresses poor appetite due to Spleen deficiency (insufficient Mingmen Fire) and diarrhea due to excessive Dampness (Spleen Earth is controlled by Liver Wood and fails to manage Water. Ancient diuretic formulas often use Cassia, such as Wuling San and Zishen Wan), tonifies chronic weakness and brightens eyes, unblocks menstruation, and induces abortion (because pungent and hot herbs move Blood).
Those from Guizhou in Lingnan are superior (the prefecture is named after Cassia). Those with purple color, thick flesh, and pungent-sweet taste are called Rou Gui (Cortex Cinnamomi / Cassia Bark) (enters Liver, Kidney, Mingmen). Use after removing the rough bark (toxicity resides in the bark); remove outer and inner layers, taking only the center, called Guixin (Cassia Core) (enters Heart); tender bark from twigs is called Guizhi (Cassia Twig) (enters Lung, Bladder, and Hand-Foot channels). Harmonizes well with Ginseng Radix et Rhizoma (Renshen), Licorice Root (Gancao), and Ophiopogon Tuber ( Maidong). Avoid raw Scallion (Cong Bai) and Red Halloysite (Shizhi) (Bencao distinguishes between Jun Gui, Tong Gui, Mu Gui, and Ban Gui. Current usage rarely distinguishes them; only those with thick flesh and strong aroma are considered good).