燥，补阳，活血
苦入心，辛走血。能引血、化汗、化脓，内托痈、疽、痘疮（同丁香，治痘疮灰塌），
益精明目，消瘀生肌，补劳伤，暖腰膝，续筋骨。
治风痹症瘕，噎膈腹满，腹内冷痛，九种心痛（一虫、二疰、三风、四悸、五食、六饮
、七冷、八热、九去来痛，皆邪乘于手少阴之络，邪正相激，故令心痛）。
轻，解肌，调营卫
辛甘而温，气薄升浮。入太阴肺、太阳膀胱经。温经通脉，发汗解肌（能利肺气。经曰
∶辛甘发散为阳）。
治伤风头痛（无汗能发），中风自汗（有汗能止。中，犹伤也，古文通用，自汗属阳虚。
桂枝为君，芍药，甘草为佐。加姜、枣名桂枝汤，能和营实表），调和营卫，使邪从汗
出，而汗自止。亦治手足痛风、胁风（痛风有风痰、风湿、湿痰、瘀血、气虚、血虚之异。
桂枝用作引经。胁风属肝，桂能平肝。东垣曰∶桂枝横行手臂，以其为枝也。又曰∶气薄则
发泄，桂枝上行而解表。气浓则发热，肉桂下行而补肾。王好古曰∶或问桂枝止烦出汗，仲
景治伤寒发汗，数处皆用桂枝汤。又曰无汗不得用桂枝，汗多者桂枝甘草汤，此又能闭汗也，
二义相通否乎？曰∶仲景云太阳病发热汗出者，此为营弱卫强。阴虚，阳必凑之，故以桂枝
发其汗，此乃调其营气，则卫气自和，风邪无所容，遂自汗而解，非若麻黄能开腠理，发出
其汗也。汗多用桂枝者，以之调和营卫，则邪从汗出，而汗自止，非桂枝能闭汗孔也，亦惟
有汗者宜之。若伤寒无汗，则当以发汗为主，而不独调其营卫矣！故曰无汗不得服桂枝，有
汗不得服麻黄也。《伤寒例》曰∶桂枝下咽，阳盛则毙；承气入胃，阴盛则亡）。
性味辛、苦，具有燥湿、补阳、活血的功效。
苦味入心经，辛味走血分。能够引导血液运行、促进发汗、化生脓液，内托治疗痈疽和痘疮（与丁香功效相同，可治疗痘疮塌陷），
填补精髓、明亮双目、消除瘀血、促进肌肉生长、补益虚劳损伤、温暖腰膝、接续筋骨。
治疗风痹症瘕、噎膈腹满、腹部冷痛、九种心痛（即虫心痛、疰心痛、风心痛、悸心痛、食心痛、饮心痛、冷心痛、热心痛、往来痛，都是邪气侵袭手少阴心经络脉，邪正相争，所以导致心痛）。
质地轻清，能解肌表之邪，调和营卫。
气味辛甘而温，气机轻薄升浮。归入太阴肺经、太阳膀胱经。温通经脉、畅通血脉、发汗解肌（能宣利肺气。医经说：辛甘发散属于阳）。
治疗伤风头痛（无汗时能发汗）、中风自汗（有汗时能止汗。“中”同“伤”，古文通用，自汗属于阳虚。以桂枝为君药，芍药、甘草为佐药。加入生姜、大枣称为桂枝汤，能调和营气充实体表），调和营卫，使邪气随汗排出，从而汗自停止。也治疗手足痛风、胁部风邪（痛风有风痰、风湿、湿痰、瘀血、气虚、血虚等不同类型。桂枝用作引经药。胁风属于肝经病变，桂枝能平抑肝气。李东垣说：桂枝横行于手臂，因为它是枝条的缘故。又说：气薄则发泄，桂枝上行而解表；气浓则发热，肉桂下行而补肾。王好古说：有人问桂枝为何能止烦出汗，张仲景治疗伤寒发汗，多处都用桂枝汤。又说无汗不能用桂枝，汗多者用桂枝甘草汤，这又能闭汗，这两种说法相通吗？回答说：张仲景说太阳病发热汗出，这是营弱卫强。阴虚，阳气必凑集于此，所以用桂枝发其汗，这是调和营气，那么卫气自然和谐，风邪无处容身，于是随汗而解，不像麻黄能开泄腠理强行发出汗来。汗多用桂枝的，是用它调和营卫，使邪气从汗而出，汗自然停止，并非桂枝能关闭汗孔，也只有有汗的人适宜使用。如果伤寒无汗，则应当以发汗为主，而不只是调和营卫了！所以说无汗不能服桂枝，有汗不能服麻黄。《伤寒例》说：桂枝下咽，若阳气盛则会致死；承气汤入胃，若阴气盛则会亡）。
Pungent and bitter in flavor, it dries dampness, tonifies Yang, and invigorates blood.
Bitter enters the Heart, pungent travels through the Blood. It can guide blood circulation, induce sweating, transform pus, internally support the expulsion of toxins in carbuncles and sores (similar to Dingxiang [Caryophylli Flos], treating collapsed smallpox),
nourishes essence, brightens the eyes, eliminates stasis, generates flesh, tonifies labor injuries, warms the waist and knees, and reconnects sinews and bones.
Treats wind-bi with masses, dysphagia with abdominal fullness, cold pain in the abdomen, and nine types of heartache (namely worm, zhu [malaria-like pathogen], wind, palpitation, food, fluid, cold, heat, and wandering pain; all are caused by pathogens invading the collaterals of the Hand-Shaoyin [Heart] meridian, where pathogenic and righteous qi clash, thus causing heartache).
Light in nature, it releases the muscle layer and harmonizes Ying and Wei.
Pungent, sweet, and warm in flavor, its Qi is light, ascending, and floating. Enters the Taiyin Lung and Taiyang Bladder meridians. Warms the meridians, unblocks vessels, induces sweating, and releases the muscle layer (can benefit Lung Qi. The classic states: Pungent and sweet dispersing actions belong to Yang).
Treats wind-cold headache (induces sweating when there is no sweat), stroke with spontaneous sweating (stops sweating when present. "Zhong" [strike] is synonymous with "Shang" [injure], commonly used in ancient texts; spontaneous sweating belongs to Yang deficiency. Guizhi [Ramulus Cinnamomi] serves as the Sovereign herb, Shaoyao [Radix Paeoniae Rubra or Alba] and Gancao [Radix Glycyrrhizae] as ministers. Adding Shengjiang [Rhizoma Zingiberis Recens] and Dazao [Fructus Jujubae] forms Guizhi Tang [Cinnamon Twig Decoction], which can harmonize Ying and solidify the exterior), harmonizes Ying and Wei, allowing pathogens to exit via sweat, thereby stopping spontaneous sweating. Also treats gout in hands and feet, and wind affecting the hypochondrium (gout varies into wind-phlegm, wind-dampness, damp-phlegm, blood stasis, Qi deficiency, and Blood deficiency. Guizhi acts as a guiding herb. Hypochondriac wind belongs to the Liver; Cinnamomum can soothe the Liver. Li Dongyuan stated: Guizhi traverses the arms horizontally because it is a twig. He also said: Light Qi dissipates; Guizhi ascends to release the exterior. Dense Qi generates heat; Rougui [Cortex Cinnamomi] descends to tonify the Kidney. Wang Haogu stated: Someone asked why Guizhi stops irritability and induces sweating. Zhang Zhongjing used Guizhi Tang in many places for inducing sweating in Shanghan [Cold Damage]. He also said that Guizhi should not be used when there is no sweat, while Guizhi-Gancao Tang is used when sweat is excessive, which seems to close sweat pores. Are these two meanings consistent? The answer is: Zhang Zhongjing said that in Taiyang disease with fever and sweating, this indicates weak Ying and strong Wei. When Yin is deficient, Yang must gather there, so Guizhi is used to induce sweating. This actually harmonizes Ying Qi, so Wei Qi becomes balanced, leaving no room for wind pathogens, and they resolve with sweat. This is different from Mahuang [Herba Ephedrae], which opens the cou li [skin pores] to forcibly expel sweat. When sweat is excessive, Guizhi is used to harmonize Ying and Wei, allowing pathogens to exit with sweat, thus stopping the sweat; it does not close the sweat pores. It is suitable only for those with existing sweat. If Shanghan presents with no sweat, the primary treatment should be inducing sweating, not merely harmonizing Ying and Wei! Therefore, it is said that Guizhi should not be taken when there is no sweat, and Mahuang should not be taken when there is sweat. The Shanghan Li [Example of Cold Damage] states: If Guizhi is swallowed and Yang is excessive, death ensues; if Chengqi Tang [Gastro-Intestinal Purging Decoction] enters the stomach and Yin is excessive, death ensues).