- Restless legs syndrome
- Restlessness
- Reston virus
- Restorative justice
- Restricted randomization
- Restriction digest
- Restriction endonucleases
- Restriction enzymes
- Restriction fragments
- Restriction maps
- Restriction modification system
- Restriction point
- Restriction sites
- Restrictive cardiomyopathy
- Restrictive lung disease
- Restylane
- Resuscitation
- Resuscitative endovascular balloon occlusion of the aorta
- Resuscitative thoracotomy
- Resuscitator
- Retained antrum syndrome
- Retained placenta
- Retainer
- Retapamulin
- Retardation factor
- Retarders
- Retching
- Rete mirabile
- Rete pegs
- Rete testis
- Retention factor
- Retention time
- Reteplase
- Reticular activating system
- Reticular cells
- Reticular dermis
- Reticular dysgenesis
- Reticular fibers
- Reticular formation
- Reticulate evolution
- Reticulin
- Reticuline
- Reticulocyte
- Reticulocyte count
- Reticulocyte index
- Reticulocyte production index
- Reticulocytopenia
- Reticulocytosis
- Reticuloendothelial system
- Reticulohistiocytoma
- Reticulohistiocytosis
- Reticulospinal tract
- Reticulum
- Retifanlimab
- Retigabine
- Retina
- Retinacula
- Retinal
- Retinal correspondence
- Retinal degeneration
- Retinal dehydrogenase
- Retinal detachment
- Retinal diseases
- Retinal dysplasia
- Retinal dystrophy
- Retinal ganglion cells
- Retinal migraine
- Retinal nerve fiber layer
- Retinal pigment epithelium
- Retinal vasculitis
- Retinal vessel analysis
- Retinitis
- Retinitis pigmentosa
- Retinoblastoma
- Retinoblastoma protein
- Retinohypothalamic tract
- Retinoic acid
- Retinoic acid receptor
- Retinoic acid receptor alpha
- Retinoic acid receptor beta
- Retinoic acid receptor gamma
- Retinoic acid syndrome
- Retinoid X receptor
- Retinoid X receptor alpha
- Retinoid X receptor gamma
- Retinoid receptor
- Retinoid x receptor
- Retinoids
- Retinol
- Retinol binding protein
- Retinol binding protein 4
- Retinol dehydrogenase
- Retinol-binding protein
- Retinopathy
- Retinopathy of prematurity
- Retinoschisis
- Retinoscopy
- Retinotopy
- Retinyl acetate
- Retinyl palmitate
- Retractor
- Retrobulbar block
- Retrobulbar hemorrhage
- Retrocalcaneal bursitis
- Retrognathia
- Retrognathism
- Retrograde amnesia
- Retrograde ejaculation
- Retrograde perfusion
- Retrograde signaling
- Retrograde tracing
- Retrolisthesis
- Retromammary space
- Retromandibular vein
- Retromer
- Retronasal smell
- Retroperitoneal
- Retroperitoneal fibrosis
- Retroperitoneal hemorrhage
- Retroperitoneal lymph node dissection
- Retropharyngeal abscess
- Retropharyngeal lymph nodes
- Retropharyngeal space
- Retropubic space
- Retrospective cohort study
- Retrospective diagnosis
- Retrospective memory
- Retrospective study
- Retrosplenial cortex
- Retrotransposons
- Retroverted uterus
- Retroviral aspartyl protease
- Retroviridae
- Retroviruses
- Rett syndrome
- Reuptake
- Reuptake inhibitor
- Reutericyclin
- Reuterin
- Rev-Erb
- Rev-erba
- Revascularization
- Revefenacin
- Reversal potential
- Reversal test
- Reverse Transcription Loop-mediated Isothermal Amplification
- Reverse causation
- Reverse cholesterol transport
- Reverse electron flow
- Reverse genetics