- Rote learning
- Rotenone
- Rothia
- Rothia dentocariosa
- Rothia mucilaginosa
- Rothmund-Thomson syndrome
- Rotigotine
- Rotor syndrome
- Rotterdam Study
- Rough endoplasmic reticulum
- Rough-and-tumble play
- Roughage
- Roughness
- Rouleaux
- Round ligament
- Round ligament of the liver
- Round ligament of the uterus
- Round window
- Roundup
- Rous sarcoma virus
- Routes of administration
- Roux en y gastric bypass
- Roux-en-Y
- Roux-en-y
- Rovalpituzumab tesirine
- Rovsing's sign
- Roxadustat
- Roxithromycin
- Royal jelly
- RpoB
- Rpob
- Rs4680
- Rs6265
- Rubber band ligation
- Rubber cement
- Rubber dam
- Rubbing alcohol
- Rubella
- Rubella vaccine
- Rubella virus
- Rubeosis iridis
- Rubinstein-Taybi Syndrome
- Rubinstein-Taybi syndrome
- Rubisco
- Rubivirus
- Ruboxistaurin
- Rubratoxin
- Rubrospinal tract
- Rubus
- Rubus idaeus
- Rubus occidentalis
- Ruby laser
- Rucaparib
- Rudimentary horn pregnancy
- Rudiviridae
- Rufinamide
- Rugae
- Rule of Rescue
- Rule of Six
- Rumack-Matthew nomogram
- Rumen
- Rumex crispus
- Rumination
- Rumination syndrome
- Ruminococcaceae
- Ruminococcus
- Run-in period
- Running economy
- Running-related injuries
- Runx2
- Runx3
- Rupatadine
- Rupintrivir
- Ruptured spleen
- Russell bodies
- Rut
- Ruta
- Ruta chalepensis
- Ruta graveolens
- Rutile
- Rutin
- Rutinose
- RuvC
- Ruxolitinib
- RxNorm
- Ryanodine
- Ryanodine receptor
- Ryanodine receptor 1
- Ryanodine receptor 2
- Rye
- S 100 protein
- S cell
- S phase
- S-23
- S-Adenosyl-L-homocysteine
- S-Glutathionylation
- S-Methylcysteine
- S-Nitroso-N-acetylpenicillamine
- S-Nitrosoglutathione
- S-Nitrosothiol
- S-Nitrosylation
- S-layer
- S-ribosylhomocysteine lyase
- S100
- S100-A1
- S100-A4
- S100A10
- S100A11
- S100A12
- S100A13
- S100A14
- S100A16
- S100A2
- S100A6
- S100A7
- S100A8
- S100A9
- S100B
- S100P
- S1PR1
- S1PR2
- S9 fraction
- SAD PERSONS scale
- SAID principle
- SALL1
- SALL4
- SAMtools
- SAPHO syndrome
- SAPS II
- SARM1
- SARPE
- SARS
- SARS coronavirus
- SARS virus
- SARS-CoV-2
- SASP
- SAXS
- SB-271046
- SB-366791
- SB-431542
- SB-705498
- SBR
- SCCmec
- SCN1A
- SCN1B
- SCN2A
- SCN5A
- SCN8A
- SCNN1A
- SCNN1B