- Bucket handle fracture (semilunar cartilage) (see also Tear, meniscus) 836.2
- Budd-Chiari syndrome (hepatic vein thrombosis) 453.0
- Budgerigar-fanciers' disease or lung 495.2
- Büdinger-Ludloff-Läwen disease 717.89
- Buds
- Buerger's disease (thromboangiitis obliterans) 443.1
- Bulbar - see condition
- Bulbus cordis 745.9
- Bulging fontanels (congenital) 756.0
- Bulimia 783.6
- Bulky uterus 621.2
- Bulla(e) 709.8
- Bullet wound - see also Wound, open, by site
- Bullis fever 082.8
- Bullying (see also Disturbance, conduct) 312.0
- Bundle
- Bungpagga 040.81
- Bunion 727.1
- Bunionette 727.1
- Bunyamwera fever 066.3
- Buphthalmia, buphthalmos (congenital) 743.20
- Bürger-Grütz disease or syndrome (essential familial hyperlipemia) 272.3