- Bezold's abscess (see also Mastoiditis) 383.01
- Bianchi's syndrome (aphasia-apraxia-alexia) 784.69
- Bicornuate or bicornis uterus (complete) (partial) 752.34
- Bicuspid aortic valve 746.4
- Biedl-Bardet syndrome 759.89
- Bielschowsky's disease 330.1
- Bielschowsky-Jansky
- Biemond's syndrome (obesity, polydactyly, and intellectual disabilities) 759.89
- Biermer's anemia or disease (pernicious anemia) 281.0
- Biett's disease 695.4
- Bifid (congenital) - see also Imperfect, closure
- Biforis uterus (suprasimplex) 752.34
- Bifurcation (congenital) - see also Imperfect, closure
- Big spleen syndrome 289.4
- Bigeminal pulse 427.89
- Bigeminy 427.89
- Bilateral - see condition
- Bile duct - see condition
- Bile pigments in urine 791.4
- Bilharziasis (see also Schistosomiasis) 120.9
- Biliary - see condition
- Bilious (attack) - see also Vomiting
