Diarrhea or diarrhœa (from the Greek διάρροια from διά dia "through" and ῥέω rheo "flow") is the condition of having at least three loose or liquid bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin with loss of the normal stretchiness of the skin and changes in personality. This can progress to decreased urination, loss of skin color, a fast heart rate, and adecrease in responsiveness as it becomes more severe. Loose but non watery stools in babies who are breastfed; however, may be normal.[2]
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腹瀉({{lang-en|diarrhea, diarrhœa}} 來自{{lang-gr|διάρροια}}，包含兩個字根：「διά /dia ，經過」，以及「ῥέω/rheo，流動」)的定義是在一天之內有軟便或水便的狀況而且[[排便]]三次以上<!-- <ref name=WHO2013/> -->，症狀常持續好幾天而且可能因為體液流失的關係而產生[[脫水]]現象<!-- <ref name=WHO2013/> -->。脫水的初期表現是皮膚失去彈性，而且人格出現變化<!-- <ref name=WHO2013/> -->。如果脫水的情形繼續惡化，接下來可能會出現[[排尿]]量減少、膚色蒼白、[[心跳過速]]、或者對外界刺激反應不佳<!-- <ref name=WHO2013/> -->。另外，對以[[母乳餵養]]的嬰兒來說，軟便可能是正常的現象<ref name=WHO2013/>。
The most common cause is an infection of the intestines due to either a virus, bacteria, or parasite, a condition known as gastroenteritis. These infections are often acquired from food or water that has been contaminated by stool, or directly from another person who is infected. It may be divided into three types: short duration watery diarrhea, short duration bloody diarrhea, and if it lasts for more than two weeks persistent diarrhea. The short duration watery diarrhea may be due to an infection by cholera. If blood is present it is also known as dysentery.[2]A number of non-infectious causes may also result in diarrhea including: hyperthyroidism, lactose intolerance,inflammatory bowel disease, a number of medications, and irritable bowel syndrome among other.[3] In most cases stool cultures are not required to confirm the exact cause.[4]
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最常見的原因為[[腸道]]感染，可能是[[病毒]]、[[細菌]]、或[[寄生蟲]]感染，也就是一般所謂的「[[腸胃炎]]」<!-- <ref name=WHO2013/> -->。主要是透過與病人的密切接觸<!-- <ref name=WHO2013/> -->（例如：透過與病人分享食物、水、器皿、接觸到病人的嘔吐物、排泄物或病人曾接觸的物體表面）、吃或喝到污染的食物或飲料等途徑傳染。非感染性原因如：[[甲狀腺機能亢進]]、[[乳糖不耐症]]、[[炎症性腸病|發炎性腸道疾病]]、藥物、[[大腸激躁症]]等因素<ref name=CEM2013>{{cite book|last1=Doyle|first1=edited by Basem Abdelmalak, D. John|title=Anesthesia for otolaryngologic surgery|date=2013|publisher=Cambridge University Press|location=Cambridge|isbn=1107018676|pages=282-287}}</ref> 。另外依症狀持續時間可分為急性腹瀉(小於兩周)、持續性腹瀉(二至四周)、慢性腹瀉(大於四周)<ref name=HPIM2011>{{cite book|last1=Longo|first1=Dan|last2=Fauci |first2=Anthony|last3=Kasper |first3=Dennis|last4=Hauser |first4=Stephen|last5=Jameson |first5=J.|last6=Loscalzo |first6=Joseph |title=Harrison’s Principles of Internal Medicine |date=2011|publisher=McGraw-Hill |isbn= 9780071748896 |pages=第40章}}</ref>。急性水樣腹瀉其中一個原因為[[霍亂]]弧菌感染。出血性腹瀉，也就是糞便中帶血，又稱為「[[痢疾]]」(Dysentery)<ref name=WHO2013/>。大部分情況不需做糞便培養確定病原<ref name=NEJM2014/>。
Prevention of infectious diarrhea is by improved sanitation, clean drinking water, and hand washing. Breastfeeding for at least six month is also recommended as is vaccination against rotavirus. Oral rehydration solution (ORS), which is clean water with modest amounts of salts and sugar, along with zinc tablets are the treatments of choice.[2] This treatment have been estimated to have saved 50 million children in the past 25 years.[1] When people have diarrhea it is recommended that they continue to eat healthy food and babies continue to be breastfeed.[2] If commercial ORS are not available, homemade solutions may be used.[5] In those with severe dehydration, intravenous fluids may be required.[2] Most cases; however, can be managed well with fluids by mouth.[6] Antibiotics, while rarely used, may be recommended in a few cases such as those who have bloody diarrhea and a high fever, those with severe diarrhea following travelling, and those who grow specific bacteria or parasites in their stool.[4] Loperamide may help decrease the number of bowel movement but is not recommended in those with severe disease.[4]
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感染性腹瀉的預防方式包括：改善[[環境衛生]]、確保[[飲用水]]的潔淨以及勤[[洗手]]。讓嬰兒持續哺乳至少六個月，並施打[[輪狀病毒疫苗]]也是推薦的預防方式<ref name=WHO2013/>。在治療方面，給病人服用[[口服脫水補充液]]（乾淨的飲用水加上適量的鹽、[[糖]]、以及[[鋅片]]）<ref>{{cite web|author1=ACEP|title=Nation’s Emergency Physicians Announce List of Test and Procedures to Question as Part of Choosing Wisely Campaign|url=http://www.choosingwisely.org/nations-emergency-physicians-announce-list-of-test-and-procedures-to-question-as-part-of-choosing-wisely-campaign/|website=Choosing Wisely|accessdate=18 June 2014}}</ref>，如果說買不到口服脫水補充液，可以參考配方自行配製<ref name=Prober2012>{{cite book|last1=Prober|first1=edited by Sarah Long, Larry Pickering, Charles G.|title=Principles and practice of pediatric infectious diseases|date=2012|publisher=Elsevier Saunders|location=Edinburgh|isbn=9781455739851|page=96|edition=4th ed.|url=http://books.google.ca/books?id=TN2Gu2Af1BIC&pg=PA96}}</ref>，口服脫水補充療法在過去25年內拯救了五千萬名孩童免於因腹瀉造成的脫水或電解質不平衡而死亡<ref name=WHO2010a>{{cite web |url=http://whqlibdoc.who.int/publications/2009/9789241598415_eng.pdf |title=whqlibdoc.who.int |format=PDF |work=[[World Health Organization]]}}</ref>。一般建議腹瀉患者仍可正常進食（如果是哺乳中的嬰幼兒則照常哺乳）<ref name=WHO2013/>。徜若病人出現嚴重的脫水症狀，則可能需要[[靜脈注射|靜脈輸液]]，但這情形並不常見，絕大多數的案例都能經口補足流失的水和電解質。腹瀉的病人很少需要抗生素，但在極少狀況下仍需要依情形給予[[抗生素]]（例如腹瀉中帶血、伴隨高燒、旅行後隨即發作的嚴重腹瀉、或是在糞便檢體中見到或培養出特定的細菌或寄生蟲<ref name=NEJM2014/>。）鹽酸洛呱丁胺(Loperamide)對減緩腸道運動可能有幫助，但並不被建議用在嚴重腹瀉的患者身上<ref name=NEJM2014>{{cite journal|last1=DuPont|first1=HL|title=Acute infectious diarrhea in immunocompetent adults.|journal=The New England journal of medicine|date=Apr 17, 2014|volume=370|issue=16|pages=1532-40|pmid=24738670}}</ref>。
About 1.7 to 5 billion cases of diarrhea occur per year.[2][3] It is most common in developing countries were young children get diarrhea on average three times a year.[2] Worldwide, as of 2012, it is the second most common cause of deaths in children less than five (0.76 million or 11%).[2][7] Frequent episodes of diarrhea are also a common cause of malnutrition and the most common cause in those less than five years of age.[2] Other long term problems that can result include poor physical and intellectual development.[7]
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全球每年有17至50億例的腹瀉病例<ref name=WHO2013/><ref name=CEM2013/>，尤其常發生在[[開發中國家]]的兒童身上（平均約一年3次<ref name=WHO2013/>）。2012年全球五歲以下[[兒童死因]]當中腹瀉排名第二（有76萬名兒童死於腹瀉，佔11%<ref name=WHO2013/><ref name=CDC2013/>）。經常發生的腹瀉也會造成五歲以下的兒童的[[營養不良]]及其他長期問題<ref name=WHO2013>{{cite web|title=Diarrhoeal disease Fact sheet N°330|url=http://www.who.int/mediacentre/factsheets/fs330/en/|website=World Health Organization|accessdate=18 June 2014|date=April 2013}}</ref>（如生長遲緩或智力發展遲緩<ref name=CDC2013>{{cite web|title=Global Diarrhea Burden|url=http://www.cdc.gov/healthywater/global/diarrhea-burden.html|website=CDC|accessdate=18 June 2014|date=January 24, 2013}}</ref>）。