An Etymological Dictionary of the German Language/verdauen

by Friedrich Kluge

verdauen, vb., ‘to digest,’ from the equiv. MidHG. verdöuwen (verdöun), verdouwen, with the simple forms döuwen, douwen, OHG. douwen (dęwen), firdouwen, ‘to digest’; comp. Du. verduwen. The assumed Teut. þaujan, ‘to digest,’ is probably connected with tauen (lit. ‘to dissolve’). —