二便皆脾胃之出路。小便是清道属气。大肠是浊道属血。失血家。血虚便燥。尤其应得。四物汤加麻仁主
之。血燥者加桃仁川军。气燥者加杏仁枳壳。风燥者加皂角白芷防风。火燥者宜加枳壳浓朴大黄芒硝。
大肠乃胃之关门。胃为燥土。若胃有燥屎而不下者。其责不在大肠。而在胃。其证口渴。手足潮热。或发谵
语。三一承气汤下之。或四物汤加麻仁枳壳浓朴大黄以滋降之。
又小便数而不禁。大便反闭者。名为脾约。谓脾津下泄。无以润肠故也。仲景用脾约丸治之。丹溪谓宜清
肺燥。肺清则小水有制。而脾得灌溉。宜用清燥救肺汤治之。
肾开窍于二阴。肾虚阴不足。无以润肠者。宜左归饮。加黑芝麻肉苁蓉治之。
肺与大肠相表里。肺遗热于大肠则便结。肺津不润则便结。肺气不降则便结。肺遗热者。人参泻肺汤治
之。肺津不润者。清燥救肺汤治之。肺气不降者。清燥救肺汤。合四磨汤。再重加杏仁。或少加葶苈子治之。
与便血条。合看自明。
此外又有瘀血闭结之证。或失血之后。血积未去。或跌打损伤。内有瘀血。停积不行。大便闭结。或时通利。
仍不多下。所下之粪。又带黑色。腹中时时刺痛。口渴发热。脉带涩象。宜用桃仁承气汤治之。或失笑散加
杏仁桃仁当归白芍。
Both urination and defecation are the exit pathways of the Spleen and Stomach. Urination belongs to the clear pathway and is associated with Qi (vital energy); the Large Intestine belongs to the turbid pathway and is associated with Blood. Patients who have suffered blood loss suffer from dry stools due to Blood deficiency, which is a natural consequence. The primary treatment should be Siwu Tang (Four Substances Decoction) added with Hemp Seed (Cannabis Fructus). If caused by Blood dryness, add Peach Kernel (Persicae Semen) and Rhubarb (Rhei Radix et Rhizoma). If caused by Qi dryness, add Apricot Kernel (Armeniacae Semen Amarum) and Immature Bitter Orange (Aurantii Fructus Immaturus). If caused by Wind dryness, add Gleditsia Sinensis Fruit (Gleditsiae Fructus), Angelica Dahurica Root (Angelicae Dahuricae Radix), and Saposhnikovia Divaricata Root (Saposhnikoviae Radix). If caused by Fire dryness, it is appropriate to add Immature Bitter Orange (Aurantii Fructus Immaturus), Magnolia Bark (Magnoliae Officinalis Cortex), Rhubarb (Rhei Radix et Rhizoma), and Mirabilite (Natrii Sulfas).
The Large Intestine serves as the "closing gate" of the Stomach. The Stomach is considered Dry Earth. If there are dry fecal masses in the Stomach that fail to descend, the responsibility lies not with the Large Intestine but with the Stomach. Symptoms include thirst, tidal fever of the hands and feet, or delirious speech (Zhenyu). It should be treated with San Yi Chengqi Tang (Three-One Purging Decoction) to purge the accumulation. Alternatively, Siwu Tang (Four Substances Decoction) added with Hemp Seed (Cannabis Fructus), Immature Bitter Orange (Aurantii Fructus Immaturus), Magnolia Bark (Magnoliae Officinalis Cortex), and Rhubarb (Rhei Radix et Rhizoma) can be used to nourish and descend.
Furthermore, if urination is frequent and involuntary, while defecation is conversely obstructed, this condition is named Pi Yue (Spleen Constraint). This implies that the fluids of the Spleen leak downward, leaving insufficient moisture to lubricate the intestines. Zhang Zhongjing used Pi Yue Wan (Spleen Constraint Pill) to treat this. Zhu Danxi suggested clearing Lung dryness; when the Lung is clear, urination becomes regulated, allowing the Spleen to receive irrigation. Qingzao Jiufei Tang (Clear Dryness and Rescue the Lung Decoction) is appropriate for treatment.
The Kidney opens into the two yin orifices (anterior and posterior). In cases of Kidney deficiency with insufficient Yin fluids failing to lubricate the intestines, Zuogui Yin (Left Restoring Decoction) added with Black Sesame Seed (Sesami Fructus Niger) and Cistanche Stem (Cistanches Herba) should be used.
The Lung and the Large Intestine are exteriorly-interiorly related. Heat transmitted from the Lung to the Large Intestine causes constipation; lack of Lung fluid lubrication causes constipation; failure of Lung Qi to descend causes constipation. For heat transmitted from the Lung, Renshen Xiefei Tang (Ginseng Draining Lung Decoction) is used. For lack of Lung fluid lubrication, Qingzao Jiufei Tang (Clear Dryness and Rescue the Lung Decoction) is used. For failure of Lung Qi to descend, Qingzao Jiufei Tang (Clear Dryness and Rescue the Lung Decoction) combined with Simo Tang (Four-Marrow Decoction), with increased dosage of Apricot Kernel (Armeniacae Semen Amarum) or a small amount of Lepidium Seed (Lepidii Semen), is used. This clarifies the matter when read together with the section on Hematochezia.
Additionally, there is the syndrome of constipation due to Blood stasis. This may occur after blood loss where stasis remains, or following traumatic injury where internal blood stasis accumulates and fails to move, leading to obstinate constipation. Although bowel movements may occasionally occur, the volume is small, and the excrement is black. There is often stabbing pain in the abdomen, accompanied by thirst, fever, and a choppy pulse. Tao Ren Chengqi Tang (Peach Kernel Purging Decoction) is indicated. Alternatively, Shixiao San (Frustrated Pain Powder) added with Apricot Kernel (Armeniacae Semen Amarum), Peach Kernel (Persicae Semen), Angelica Sinensis Root (Angelicae Sinensis Radix), and White Peony Root (Paeoniae Radix Alba) may be used.