- Rabies
- Radiation Sickness
- Ramsay Hunt Syndrome
- Raynaud's Disease
- Reactive Arthritis
- Reactive Attachment
- Rebound Headaches
- Rectal Cancer
- Rectocele
- Recurrent Breast Cancer
- Regional Pain Syndrome
- Rem Sleep Behavior Disorder
- Renal Artery Stenosis
- Restless Legs Syndrome
- Retinal Detachment
- Retinoblastoma
- Retractile Testicle
- Retrograde Ejaculation
- Rett Syndrome
- Reye'S Syndrome
- Rhabdomyolysis
- Rhabdomyosarcoma
- Rheumatic Fever
- Rheumatoid Arthritis
- Rickets
- Ringworm (Body)
- Ringworm (Scalp)
- RMSF
- Rosacea
- Roseola
- Rotator Cuff Injury
- Rotavirus
- RSV
- Rubella
- Rumination Syndrome
- Ruptured Eardrum
- Ruptured Spleen