时疫自利皆热证也，其所利之物与内虚内冷者自别。冷利之色淡白，热利之色正黄，甚有深黄、酱色者；冷利
稀薄，热利稠粘；虚冷利散而不臭，热利臭而多沫；虚冷
易出，热证努圊；冷利缓，热利暴注下迫而里急，此辨时疫热利与诸冷利之大概也。
时疫初起，有手足厥冷，恶寒，呕吐，腹痛自利者，全似太阴寒证。辨其为疫，只在口中秽气作粘，舌上白苔
粗浓，小便黄，神情烦躁，即可知其非寒中太阴，是时疫发于太阴也。烦躁轻则藿香正气散，烦躁甚则用达原饮，
一、二服后即见三阳热证矣。此时若用温中药，转见四肢逆冷，手足青紫而死，不可不细察也。
时疫初起，头疼、发热而自利，九味羌活汤。传变太阳、少阳合病，身热、口苦，咽干、目眩而自利者，黄芩
汤，兼呕加半夏。传里舌黄、谵妄而自利者，按其心下至少腹有硬痛处，与大承气汤；无硬痛处，小承气、小陷
胸、大柴胡选用。此在下其热，不必以结为主，故虽无硬痛，亦主大黄。时疫自利而小便不利，腹满而无硬块，时
作肠鸣者，热在小肠膀胱而蓄水也，四苓散、猪苓汤、益
元散选用。
时疫自利受补者少，至屡经清、下无表里证，自利渐
至清谷而脉微细者，则六君子汤、补中益气汤、理中汤，又所当酌用也。
时疫引起的自发性腹泻都属于热证，其排泄物的性状与体内虚寒者截然不同。寒性腹泻的颜色淡白，热性腹泻的颜色正黄，甚至有深黄色或酱色的；寒性腹泻质地稀薄，热性腹泻质地稠粘；虚寒性腹泻排泄物松散且无臭味，热性腹泻排泄物有臭味且多泡沫；虚寒性腹泻容易排出，热证则表现为排便时用力努责（里急后重）；寒性腹泻起病缓慢，热性腹泻则表现为急迫的暴注下利、肛门灼热且伴有腹部拘急疼痛，这是辨别时疫热利与其他寒性腹泻的大致原则。
时疫初起时，若出现手足厥冷、恶寒、呕吐、腹痛及自发性腹泻等症状，完全类似于太阴寒证。但要辨别其为疫病，关键在于口中散发秽浊之气且感觉粘腻，舌苔白而粗厚浓密，小便黄赤，神情烦躁，据此即可知道这不是寒邪直中太阴经，而是时疫邪气发于太阴经所致。若烦躁症状较轻，使用藿香正气散；若烦躁严重，则使用达原饮，服用一两次后即可显现出三阳经的热证表现。此时如果误用温中药，会导致四肢逆冷加重，手足青紫而死，因此必须仔细诊察。
时疫初起，若出现头痛、发热并伴有自发性腹泻，适用九味羌活汤。若病邪传变至太阳、少阳合病，出现身热、口苦、咽干、目眩并伴有自发性腹泻，适用黄芩汤，兼有呕吐者加半夏。若病邪传入里部，出现舌苔黄、神志不清胡言乱语并伴有自发性腹泻，按压从心下至少腹部位有硬痛感，适用大承气汤；若无硬痛感，可选用小承气汤、小陷胸汤或大柴胡汤。此处旨在清除下部之热，不必以燥屎结聚为主症，因此即使没有硬痛感，也主用大黄。时疫自发性腹泻且小便不利，腹部胀满但无硬块，偶尔出现肠鸣音，这是热邪在小肠和膀胱导致水液停蓄所致，可选用四苓散、猪苓汤或益元散。
时疫自发性腹泻患者很少能耐受补益疗法，直到经过多次清热、攻下治疗后，既无表证也无里实证，自发性腹泻逐渐发展为完谷不化（大便中有未消化的食物）且脉象微细时，则应当酌情使用六君子汤、补中益气汤或理中汤。
Spontaneous diarrhea caused by plague-qi (epidemic pathogenic factors) all belongs to heat syndromes; the nature of the excrement differs significantly from that of internal deficiency and cold. The color of cold-type diarrhea is pale white, whereas the color of heat-type diarrhea is bright yellow, and in severe cases, deep yellow or sauce-colored. Cold-type diarrhea is thin and watery, while heat-type diarrhea is thick and sticky. Deficiency-cold type excrement is loose and odorless, whereas heat-type excrement has a foul odor and contains much foam. Deficiency-cold type is easy to pass, while heat syndromes manifest as straining during defecation (Li Ji Hou Zhong). Cold-type diarrhea is slow in onset, whereas heat-type diarrhea presents as sudden violent purging with urgency, burning sensation at the anus, and abdominal cramping. These are the general principles for distinguishing heat-type diarrhea of plague-qi from various cold-type diarrheas.
At the initial stage of plague-qi, if there are symptoms such as cold extremities, aversion to cold, vomiting, abdominal pain, and spontaneous diarrhea, it completely resembles a Taiyin cold syndrome. To distinguish it as an epidemic disease, one only needs to observe a foul smell in the mouth accompanied by a sticky sensation, a thick and coarse white coating on the tongue, yellow urine, and mental restlessness. Based on these signs, it can be known that this is not cold invading the Taiyin channel directly, but rather plague-qi manifesting in the Taiyin organ. If the restlessness is mild, Huoxiang Zhengqi San (Patchouli Powder to Rectify the Qi) is used; if the restlessness is severe, Dayuan Yin (Origin-Reaching Decoction) is used. After one or two doses, heat syndromes of the Three Yang channels will appear. At this time, if warm-natured Chinese medicines are mistakenly used, it will lead to worsening cold limbs, cyanosis of the hands and feet, and death; therefore, careful examination is essential.
At the initial stage of plague-qi, if headache, fever, and spontaneous diarrhea occur, Jiuwei Qianghuo Tang (Nine-Ingredient Notopterygium Decoction) is indicated. If the pathogen transmits to a combined syndrome of Taiyang and Shaoyang, presenting with body heat, bitter taste in the mouth, dry throat, dizziness, and spontaneous diarrhea, Huangqin Tang (Scutellaria Decoction) is indicated; add Banxia (Pinellia Rhizome) if vomiting is present. If the pathogen enters the interior, presenting with a yellow tongue coating, delirium, and spontaneous diarrhea, and pressing from the epigastrium down to the lower abdomen reveals hardness and pain, Dachengqi Tang (Major Order the Qi Decoction) is indicated; if there is no hardness or pain, Xiao Chengqi Tang (Minor Order the Qi Decoction), Xiaoxianxiong Tang (Minor Chest-Harvesting Decoction), or Da Chaihu Tang (Major Bupleurum Decoction) may be selected. Here, the aim is to clear heat from the lower part; it does not primarily focus on fecal impaction. Therefore, even without hardness or pain, Dahuang (Rhubarb Root and Rhizome) is the primary herb. In cases of plague-qi spontaneous diarrhea accompanied by difficult urination, abdominal fullness without hard masses, and occasional borborygmus, this indicates water retention due to heat in the Small Intestine and Bladder. Siling San (Four-Powder Decoction), Zhuling Tang (Polyporus Decoction), or Yiyuan San (Benefit-Origin Powder) may be selected.
Patients with plague-qi spontaneous diarrhea rarely tolerate tonifying therapies. However, after repeated clearing and purging treatments, when neither exterior nor interior excess syndromes remain, and the spontaneous diarrhea gradually progresses to uncooked stool (Wan Gu Bu Hua - undigested food in feces) with a faint and fine pulse, then Liu Junzi Tang (Six-Gentlemen Decoction), Buzhong Yiqi Tang (Middle-Warming and Qi-Supplementing Decoction), or Lizhong Tang (Regulate the Middle Decoction) should be considered for use.