According to the novel "Shinsengumi Keppuroku (Record of Shinsengumi Bloodshed)" written by Ryotaro SHIBA, the cause of his death was inflammation of the middle ear, and his habit of washing his ears out with water worked negatively (This is a fiction originated by Kan SHIMOZAWA).
司馬遼太郎の小説『新選組血風録』では、死因は中耳炎で、普段から水でジャブジャブ耳を洗う癖が仇となったと記されているが（元ネタは子母澤寛の創作）。