'''Bawasir''', atau '''wasir''', '''ambeien''', '''hemoroid''', atau '''puru sembilikambeien''' adalah kondisi [[patologis]] [[membengkak (medis)|membengkak]] atau [[meradangnya]] '''hemoroid''', struktur [[sinusoid (pembuluh darah)|vaskular]] dalam [[saluran anus]] yang membantu kontrol buang air besar.<ref>{{cite book|author=Chen, Herbert|title=Illustrative Handbook of General Surgery|url=https://archive.org/details/illustrativehand00chen|publisher=Springer|location=Berlin|year=2010|page=[https://archive.org/details/illustrativehand00chen/page/n211 217]|isbn=1-84882-088-7 }}</ref><ref name=World09>{{cite journal | last1 = Schubert | first1 = MC | last2 = Sridhar | first2 = S | last3 = Schade | first3 = RR | last4 = Wexner | first4 = SD |title=What every gastroenterologist needs to know about common anorectal disorders |journal=World J Gastroenterol|volume=15 |issue=26 |pages=3201–9 |year=2009 |month=July |pmid=19598294 |pmc=2710774 |doi= 10.3748/wjg.15.3201| issn = 1007-9327 }}</ref><ref name=Review09/> Dalam kondisi fisiologisnya, bagian ini bertindak sebagai bantalan yang tersusun atas [[saluran arterio-vena]] dan [[jaringan ikat]].
