RT Journal Article SR Electronic T1 Black hairy tongue due to antibiotics JF BMJ Case Reports JO BMJ Case Reports FD BMJ Publishing Group Ltd SP e255112 DO 10.1136/bcr-2023-255112 VO 16 IS 7 A1 Okumura, Hisatoshi A1 Kawashima, Atsushi YR 2023 UL http://casereports.bmj.com/content/16/7/e255112.abstract AB