- Uniporter
- Units of selection
- Universal Design
- Universal Precautions
- Universal flu vaccine
- Universal health care
- Universal neonatal hearing screening
- University of Pennsylvania Smell Identification Test
- Unoprostone
- Unsaturated fat
- Unsaturated fatty acids
- Unspecified feeding or eating disorder
- Unstable angina
- Unsteady gait
- Untranslated regions
- Unverricht-Lundborg disease
- Upadacitinib
- Upper abdominal pain
- Upper airway resistance syndrome
- Upper esophageal sphincter
- Upper eyelid
- Upper gastrointestinal bleeding
- Upper limb
- Upper motor neuron
- Upper motor neuron lesions
- Upper motor neuron syndrome
- Upper quartile
- Upper respiratory infection
- Upper respiratory tract
- Upper respiratory tract infection
- Upper subscapular nerve
- Upper trunk
- Upregulated
- Upregulation
- Urachal cyst
- Urachal fistula
- Urachus
- Uracil
- Uracil phosphoribosyltransferase
- Uracil-DNA glycosylase
- Urapidil
- Urate
- Urea
- Urea breath test
- Urea cycle
- Urea reduction ratio
- Urea transporter
- Ureaplasma urealyticum
- Ureas
- Urease
- Ureidopenicillin
- Urelumab
- Uremia
- Uremic pericarditis
- Uremic pruritus
- Uremic toxin
- Ureohydrolase
- Ureter
- Ureteric bud
- Ureteric stent
- Ureteritis
- Ureterocele
- Ureteropelvic junction
- Ureteroscopy
- Ureterosigmoidostomy
- Ureterostomy
- Ureterovaginal fistula
- Urethral
- Urethral cancer
- Urethral caruncle
- Urethral discharge
- Urethral diverticulum
- Urethral groove
- Urethral hypermobility
- Urethral prolapse
- Urethral rupture
- Urethral sphincter
- Urethral stent
- Urethral stricture
- Urethral strictures
- Urethral syndrome
- Urethrectomy
- Urethritis
- Urethrocele
- Urethrography
- Urethropexy
- Urethroplasty
- Urethrorrhagia
- Urethrotomy
- Urethrovaginal fistula
- Urge incontinence
- Uric acid
- Uricosuric
- Uridine
- Uridine diphosphate
- Uridine diphosphate glucuronic acid
- Uridine kinase
- Uridine monophosphate
- Uridine phosphorylase
- Urinalysis
- Urinary bladder
- Urinary calcium
- Urinary casts
- Urinary catheter
- Urinary catheterization
- Urinary diversion
- Urinary frequency
- Urinary hesitancy
- Urinary incontinence
- Urinary meatus
- Urinary retention
- Urinary system
- Urinary tract
- Urinary tract infections
- Urinary tract obstruction
- Urinary tract ultrasound
- Urinary urgency
- Urination
- Urination disorders
- Urine
- Urine culture
- Urine cytology
- Urine dipstick
- Urine diversion
- Urine organic acids
- Urine pH
- Urine sediment
- Urine specific gravity
- Urine test
- Urine test strips
- Urinoma
- Urinothorax
- Urobilin
- Urobilinogen
- Urocanic acid
- Urocortin
- Urocortin II
- Urodilatin
- Urodynamic testing
- Urodynamics
- Uroflowmetry
- Urofollitropin
- Urogenital diaphragm
- Urogenital hiatus
- Urogenital sinus
- Uroguanylin
- Urogynecology
- Urokinase
- Urokinase receptor
- Urolithiasis