China 
Africa 
- Intraperitoneal
- Intraperitoneal injection
- Intrapleural pressure
- Intraretinal microvascular abnormalities
- Intrathecal
- Intrathecal baclofen pump
- Intrathecal pump
- Intratracheal instillation
- Intratubular germ cell neoplasia
- Intrauterine device
- Intrauterine growth restriction
- Intrauterine growth retardation
- Intrauterine hypoxia
- Intrauterine pressure catheter
- Intrauterine transfusion
- Intravaginal administration
- Intravasation
- Intravascular hemolysis
- Intravascular imaging
- Intravascular papillary endothelial hyperplasia
- Intravascular ultrasound
- Intravenous
- Intravenous anesthesia
- Intravenous ascorbic acid
- Intravenous immunoglobulin
- Intravenous immunoglobulin therapy
- Intravenous pyelogram
- Intravenous regional anesthesia
- Intravenous route
- Intravenous sedation
- Intravenous sodium bicarbonate
- Intravenous urography
- Intraventricular block
- Intraventricular hemorrhage
- Intravital microscopy
- Intravitreal administration
- Intravitreal implants
- Intravitreal injection
- Intravoxel incoherent motion
- Intrinsic activity
- Intrinsic asthma
- Intrinsic factor
- Intrinsic motivation
- Intrinsic pathway
- Intrinsic sympathomimetic activity
- Intrinsically disordered proteins
- Intrinsically photosensitive retinal ganglion cells
- Introducer sheath
- Introgression
- Introjection
- Intromission
- Intron
- Introspection
- Introversion
- Intrusive thoughts
- Intubation
- Intuition
- Intuitive eating
- Intussusception
- Intussusceptive angiogenesis
- Inulin
- Invadopodia
- Invagination
- Invariant chain
- Invasin
- Invasive aspergillosis
- Invasive candidiasis
- Invasive ductal carcinoma
- Invasive lobular carcinoma
- Invasive procedure
- Invasive test
- Invasive urothelial carcinoma
- Invasive ventilation
- Invasomes
- Inverse agonists
- Inverse care law
- Inverse dynamics
- Inverse probability weighting
- Inverse psoriasis
- Inverse ratio ventilation
- Inverse-variance weighting
- Inversion recovery
- Invert sugar
- Invertase
- Inverted nipples
- Inverted papilloma
- Inverted repeats
- Investigator's Brochure
- Investing layer of deep cervical fascia
- Invisible disability
- Invisible support
- Involucrin
- Involucrum
- Involuntary action
- Involuntary commitment
- Involuntary euthanasia
- Involuntary treatment
- Involution
- Involutional melancholia
- Inward-rectifier potassium channel
- IoT
- IoV
- Iodinated contrast medium
- Iodine
- Iodine 123
- Iodine 131
- Iodine compounds
- Iodine deficiency
- Iodine monochloride
- Iodine value
- Iodine-125
- Iodine-129
- Iodine-starch test
- Iodised salt
- Iodized salt
- Iodoacetamide
- Iodoacetic acid
- Iodoform
- Iodophor
- Iodothyronine deiodinase
- Ioflupane
- Iohexol
- Ion channels
- Ion chromatography
- Ion exchange
- Ion exchange chromatography
- Ion exchange resin
- Ion pumps
- Ion semiconductor sequencing
- Ion source
- Ion transport
- Ion trapping
- Ion-exchange membranes
- Ionic compound
- Ionic strength
- Ionic transfer
- Ionization
- Ionization chambers
- Ionization energy
- Ionization potential
- Ionized gas
- Ionizing radiation
- Ionomycin
- Ionophores
- Ionotropic effect
- Ionotropic glutamate receptors
- Ionotropic receptors
- Iontocaine
- Iontophoresis
- Iopanoic acid