- Suspended uterus, in pregnancy or childbirth 654.4
- Sutton and Gull's disease (arteriolar nephrosclerosis) (see also Hypertension, kidney) 403.90
- Sutton's disease 709.09
- Suture
- Swab inadvertently left in operation wound 998.4
- Swallowed, swallowing
- Swamp fever 100.89
- Swan neck hand (intrinsic) 736.09
- Sweat(s), sweating
- Sweeley-Klionsky disease (angiokeratoma corporis diffusum) 272.7
- Sweet's syndrome (acute febrile neutrophilic dermatosis) 695.89
- Swelling
- Swift's disease 985.0
- Swimmers'
- Swimming in the head 780.4
- Swollen - see also Swelling
- Swyer's syndrome (XY pure gonadal dysgenesis) 752.7
- Swyer-James syndrome (unilateral hyperlucent lung) 492.8
- Sycosis 704.8
- Sydenham's chorea - see Chorea, Sydenham's
- Sylvatic yellow fever 060.0
- Sylvest's disease (epidemic pleurodynia) 074.1