和脾舒筋、涩敛肺。
酸涩而温。和脾理胃。敛肺伐肝。化食（酸能敛、敛则化、与山楂同。）止渴。（酸能生
津。）
气脱能收。气滞能和，调营卫，利筋骨。（筋急者、得之即舒、筋缓者、遇之即利。）去湿热
。消水胀。治霍乱转筋。（邪伤脾胃、清浊不分、挥霍扰乱、上吐下泻、甚则肝木乘脾、而
筋为之转也、时珍曰∶肝虽主筋、而转筋则因风寒湿热袭伤脾胃所致、转筋必起于足腓、腓
及宗筋、皆属阳明、木瓜治转筋、取其理脾以伐肝也、土病则金衰而木盛、故用酸温以收脾
肺之耗散、而借其走筋以平肝邪、乃土中泻木以助金也。）泻痢香港脚。（脾主四肢、或寒湿伤
于足络、或胃受湿热之物、上输于脾、下流至足、则成香港脚、恶寒发热、状类伤寒、第胫肿
掣痛为异尔、宜利湿清热、忌用补剂及淋洗、昔有患足痹者、趁舟、见舟中一袋、以足倚之
、比及登岸、足已善步矣、询袋中何物、乃木瓜也。）腰足无力。多食损齿及骨。病癃闭。
（酸收太甚、郑奠一曰∶木瓜乃酸涩之品、世用治水肿腹胀误矣、有大寮、舟过金陵、爱其
芬馥、购数百颗、置之舟中、举舟人皆病溺不得出、医以通利罔效、迎予视之、闻四面皆木
瓜香、笑谓诸人曰∶撤去此物、溺即出矣、不必用药也、于是尽投江中、顷之、溺即如旧。
）陈者良。忌铁。（反花痔疮、木瓜为末、以鳝鱼身上涎调贴之、以纸护住。辟除壁虱、木
瓜切片、铺于席上。）
木瓜具有调和脾胃、舒缓筋脉、收敛肺气的作用。
其味酸、涩，性温。能调和脾胃，收敛肺气，抑制肝气过亢。
它能化解食积（因为酸味具有收敛作用，收敛之后能促进消化，这与山楂的功效类似）。
它能止渴（因为酸味能促进津液生成）。
对于气虚下陷导致的脱证，它具有收摄作用；对于气机阻滞，它具有疏通调和作用；能调理营卫之气，利养筋骨。（对于筋脉拘急者，服用后即刻舒展；对于筋脉弛缓无力者，服用后即刻有力。）
它能去除湿热。
消除水肿胀满。
治疗霍乱引起的转筋（这是因为邪气损伤了脾胃，导致清浊之气不分，挥霍扰乱肠胃，出现上吐下泻，严重时肝木乘克脾土，导致筋脉发生扭转。李时珍说：虽然肝脏主管筋脉，但转筋是由于风寒湿热侵袭损伤脾胃所致。转筋通常起于小腿肚腓肠肌处，腓肠肌及宗筋都归属于阳明经。木瓜治疗转筋，是取其调理脾胃以抑制肝邪的作用。脾土有病则肺金衰弱而肝木偏盛，所以用酸温之性的木瓜来收敛脾肺的耗散之气，并借助其走窜筋脉的特性来平抑肝邪，这属于在土中泻木以助金的方法）。
治疗痢疾和脚气病（脾主四肢，如果是寒湿伤害了足部经络，或者胃受湿热之物影响，湿热上输于脾，下流至足部，就会形成脚气病，表现为恶寒发热，症状类似伤寒，只是小腿肿胀抽痛不同罢了。应当采用利湿清热的方法，忌用补剂及淋洗疗法。过去有患足痹的人，乘船时，看见船中有一个袋子，便用脚倚靠它，等到上岸时，脚已经能正常行走自如了。询问袋中是什么东西，原来是木瓜）。
治疗腰部和足部无力。
多食会损害牙齿和骨骼。
治疗小便不通（癃闭）。（如果酸收作用太过强烈，郑奠一说：木瓜是酸涩性质的药物，世人用它治疗水肿腹胀是错误的。曾有一位官员，乘船经过金陵，喜爱木瓜的芬芳，购买了数百颗，放在船舱里，结果全船的人都患了尿潴留无法排尿。医生用通利小便的药物无效，请我去诊治。我闻到四周都是木瓜的香气，笑着对众人说：撤去这些东西，小便自然就能排出，不必用药。于是将木瓜全部投入江中，不久之后，患者的尿液就恢复正常了。）
陈年的木瓜药效更好。
忌与铁器接触。（木瓜粉末可用于治疗反花痔，用黄鳝身上的黏液调匀后贴敷患处，并用纸保护固定。切片铺在席子上可以驱除壁虱/臭虫。）
Mu Gua (Chaenomeles Fruit) harmonizes the spleen, relaxes sinews, and astringes the lungs.
Its flavor is sour and astringent, and its nature is warm. It harmonizes the spleen and regulates the stomach, astringes the lungs, and subdues the liver.
It transforms food stagnation (sourness has an astringent property; astringency leads to transformation, similar to Shan Zha [Crataegi Fructus]).
It relieves thirst (sourness generates body fluids).
In cases of Qi collapse, it can secure and retain Qi; in cases of Qi stagnation, it can harmonize and move it. It regulates Ying and Wei (Defensive and Nutritive Qi), and benefits sinews and bones. (For those with tight sinews, relief comes immediately upon ingestion; for those with flaccid sinews, strength returns immediately.)
It dispels damp-heat.
It reduces edema and distension.
It treats Huo Luan (cholera-like syndrome) with muscle cramps (This occurs when pathogenic factors damage the spleen and stomach, causing turbid and clear Qi to mix chaotically, resulting in violent vomiting and diarrhea. Severe cases involve Liver Wood overacting on Spleen Earth, causing sinew torsion. Li Shizhen stated: Although the Liver governs the sinews, torsion is caused by wind-cold-damp-heat invading and damaging the spleen and stomach. Torsion typically begins in the calf muscles (Fei), which belong to the Yangming channel. Mu Gua treats torsion by regulating the spleen to subdue the liver. When Spleen Earth is diseased, Lung Metal weakens and Liver Wood becomes excessive. Thus, sour-warm Mu Gua is used to gather the dissipating Qi of the spleen and lungs, and leveraging its affinity for sinews to calm Liver pathogens. This is "draining Wood within Earth to assist Metal.")
It treats dysentery and Hong Zhang Jiao (foot-leg qi / beriberi). (The Spleen governs the four limbs. If cold-dampness injures the foot collaterals, or if the Stomach absorbs damp-heat which transmits upward to the Spleen and flows downward to the feet, Hong Zhang Jiao develops. Symptoms include aversion to cold and fever, resembling Taiyang disease, but distinguished by swelling and pulling pain in the shins. Treatment should focus on promoting urination to drain dampness and clearing heat; tonics and external washing are contraindicated. In the past, a patient with foot numbness was on a boat and leaned his foot against a bag. Upon disembarking, he could walk normally. He asked what was in the bag, and it was Mu Gua.)
It treats weakness of the waist and feet.
Excessive consumption damages teeth and bones.
It treats Long Bi (difficulty in urination / urinary retention). (If the astringent effect is too strong, Zheng Dianyi noted: Mu Gua is a sour-astringent substance; using it for edema and abdominal distension is incorrect. An official traveling by boat through Jinling loved its fragrance and bought hundreds of pieces, placing them in the cabin. All crew members suffered from urinary retention that could not be relieved. Medications for promoting urination were ineffective. I was summoned and smelled the fragrance of Mu Gua everywhere. Laughing, I said to the group: Remove this item, and urination will resume without medication. The Mu Gua was thrown into the river, and shortly after, urination returned to normal.)
Aged Mu Gua is superior.
Avoid iron. (Mu Gua powder mixed with slime from eel bodies can be applied to treat Fan Hua hemorrhoids, protected with paper. Slices of Mu Gua spread on mats repel bedbugs.)