- Sternum bifidum 756.3
- Sternutation 784.99
- Steroid
- Stevens-Johnson disease or syndrome (erythema multiforme exudativum) 695.13
- Stewart-Morel syndrome (hyperostosis frontalis interna) 733.3
- Sticker's disease (erythema infectiosum) 057.0
- Stickler syndrome 759.89
- Sticky eye 372.03
- Stieda's disease (calcification, knee joint) 726.62
- Stiff
- Stiff-baby 759.89
- Stiff-man syndrome 333.91
- Stiffness, joint NEC 719.50
- Stigmata, congenital syphilis 090.5
- Still's disease or syndrome 714.30
- Still-Felty syndrome (rheumatoid arthritis with splenomegaly and leukopenia) 714.1
- Stillbirth, stillborn NEC 779.9
- Stiller's disease (asthenia) 780.79
- Stilling-Türk-Duane syndrome (ocular retraction syndrome) 378.71
- Stimulation, ovary 256.1
- Sting (animal) (bee) (fish) (insect) (jellyfish) (Portuguese man-o-war) (wasp) (venomous) 989.5
- Stippled epiphyses 756.59