- Blackwater fever 084.8
- Bladder - see condition
- Blast
- Blastomycosis, blastomycotic (chronic) (cutaneous) (disseminated) (lung) (pulmonary) (systemic) 116.0
- Bleb(s) 709.8
- Bleeder (familial) (hereditary) (see also Defect, coagulation) 286.9
- Bleeding (see also Hemorrhage) 459.0
- Blennorrhagia, blennorrhagic - see Blennorrhea
- Blennorrhea (acute) 098.0
- Blepharelosis (see also Entropion) 374.00
- Blepharitis (eyelid) 373.00
- Blepharochalasis 374.34
- Blepharoclonus 333.81
- Blepharoconjunctivitis (see also Conjunctivitis) 372.20
- Blepharophimosis (eyelid) 374.46
- Blepharoplegia 374.89
- Blepharoptosis 374.30
- Blepharopyorrhea 098.49
- Blepharospasm 333.81
- Blessig's cyst 362.62
- Blighted ovum 631.8
- Blind
