China 
Africa 
- Submandibular lymph nodes
- Submandibular space
- Submandibular triangle
- Submental artery
- Submental lymph nodes
- Submental space
- Submental triangle
- Submucosa
- Submucosal glands
- Submucous plexus
- Suboccipital muscle
- Suboccipital puncture
- Suboccipital triangle
- Suboptimal health
- Suboxone
- Subphrenic abscess
- Subplate
- Subpopulation
- Subscapular artery
- Subscapular nerve
- Subscapular nerves
- Subscapularis
- Subscapularis muscle
- Subserosa
- Subspecialty
- Subspecies
- Substance P
- Substance abuse
- Substance abuse prevention
- Substance intoxication
- Substance of Very High Concern
- Substance use disorder
- Substance-induced psychosis
- Substance-related disorder
- Substance-related disorders
- Substantia innominata
- Substantial equivalence
- Substituents
- Substituted amphetamines
- Substituted cathinones
- Substitution matrix
- Substrate
- Substrate analog
- Substrate level phosphorylation
- Substrate reduction therapy
- Substrate specificity
- Subtalar joint
- Subtelomere
- Subthalamic nucleus
- Subtilase
- Subtilisin
- Subtractive hybridization
- Subungual exostosis
- Subungual hematoma
- Subunit vaccine
- Subventricular zone
- Subvocalization
- Success
- Successful aging
- Succinate
- Succinate dehydrogenase
- Succinate—CoA ligase
- Succinic acid
- Succinic semialdehyde
- Succinic semialdehyde dehydrogenase deficiency
- Succinimide
- Succinylacetone
- Succinylation
- Succinylcholine
- Sucralfate
- Sucralose
- Sucrase
- Sucrase-isomaltase
- Sucrose
- Sucrose esters
- Sucrose intolerance
- Sucrose synthase
- Suction
- Suction catheter
- Sudan ebolavirus
- Sudan stain
- Sudden arrhythmic death syndrome
- Sudden cardiac death
- Sudden cardiac death of athletes
- Sudden death
- Sudden sensorineural hearing loss
- Sudden unexpected death in epilepsy
- Sudden unexplained death in childhood
- Sudomotor
- Sufentanil
- Suffering
- Suffocation
- Sugammadex
- Sugar acid
- Sugar acids
- Sugar alcohols
- Sugar phosphate
- Sugar production
- Sugaring
- Suggestibility
- Suicidal behavior
- Suicidal ideation
- Suicidality
- Suicide
- Suicide attempt
- Suicide gene
- Suicide inhibition
- Suicide intervention
- Suicide prevention
- Suicide survivor
- Suicide tourism
- Suicide watch
- Sulbactam
- Sulci
- Sulconazole
- Sulcular epithelium
- Sulcus
- Sulcus limitans
- Sulcus sign
- Sulfacetamide
- Sulfadiazine
- Sulfadimethoxine
- Sulfadoxine
- Sulfaguanidine
- Sulfalene
- Sulfamerazine
- Sulfamethoxazole
- Sulfamethoxypyridazine
- Sulfanegen
- Sulfanilamide
- Sulfanilamides
- Sulfanilic acid
- Sulfapyridine
- Sulfasalazine
- Sulfatase
- Sulfate
- Sulfate reducing bacteria
- Sulfate transporter
- Sulfates
- Sulfathiazole
- Sulfatide
- Sulfation
- Sulfenamide
- Sulfenic acid
- Sulfhemoglobinemia
- Sulfide
- Sulfinpyrazone
- Sulfite
- Sulfite oxidase
- Sulfolane