Ruwan sha'ir abin sha ne da aka dafa shi da hatsin sha'ir. Ana tace ruwa don cire sha'ir kuma sau da yawa ana zaƙi da sukari ko zuma. Ana iya ba da shi zafi ko sanyi kuma ana amfani da shi azaman abin sha mai daɗi a yawancin al'adu. Bugu da ƙari, ana amfani da ruwan sha'ir sau da yawa don amfanin lafiyarsa, saboda yana da kyau tushen fiber kuma yana iya taimakawa wajen tallafawa lafiyar narkewa.