China 
Africa 
- Iopromide
- Ioversol
- Iowa gambling task
- Ipatasertib
- Ipecac
- Ipilimumab
- Ipomoea
- Ipomoea batatas
- Ipragliflozin
- Ipratropium bromide
- Iprodione
- Iproniazid
- Ipsapirone
- Irak4
- Irbesartan
- Iridectomy
- Iridocyclitis
- Iridodialysis
- Iridodonesis
- Iridoids
- Iridology
- Iridoplegia
- Iridoviridae
- Irinotecan
- Iris
- Iris coloboma
- Iris pseudacorus
- Iris scissors
- Iris sphincter muscle
- Irisin
- Iritis
- Iron
- Iron binding capacity
- Iron binding proteins
- Iron cycle
- Iron deficiency
- Iron deficiency anaemia
- Iron deficiency anemia
- Iron lung
- Iron metabolism disorders
- Iron overload
- Iron oxide
- Iron oxide nanoparticles
- Iron oxides
- Iron phosphate
- Iron poisoning
- Iron preparation
- Iron response element
- Iron sucrose
- Iron sulfur proteins
- Iron supplements
- Iron-binding proteins
- Iron-sulfur cluster
- Iron-sulfur proteins
- Irosustat
- Irradiance
- Irradiation
- Irrationality
- Irregular sleep-wake rhythm
- Irregular sleep-wake rhythm disorder
- Irreversible antagonist
- Irreversible electroporation
- Irritability
- Irritable bowel syndrome
- Irritant contact dermatitis
- Irritants
- Irvine-Gass syndrome
- Irvingia gabonensis
- Isatin
- Isatis tinctoria
- Isavuconazonium
- Ischemia
- Ischemic cardiomyopathy
- Ischemic cascade
- Ischemic colitis
- Ischemic compression
- Ischemic heart disease
- Ischemic hepatitis
- Ischemic injury
- Ischemic monomelic neuropathy
- Ischemic optic neuropathy
- Ischemic preconditioning
- Ischemic stroke
- Ischial
- Ischial spine
- Ischial tuberosity
- Ischioanal fossa
- Ischiocavernosus
- Ischiocavernosus muscle
- Ischiofemoral
- Ischiofemoral ligament
- Ischiopagi
- Isethionate
- Islet cell transplantation
- Islets of Langerhans
- Isoalloxazine
- Isoantibodies
- Isoaspartate
- Isobaric tag for relative and absolute quantitation
- Isoborneol
- Isobutanol
- Isobutene
- Isobutyl alcohol
- Isobutyl cyanoacrylate
- Isocarboxazid
- Isocenter
- Isochromosome
- Isocitrate dehydrogenase
- Isocitric acid
- Isocoumarin
- Isocyanate group
- Isocyanates
- Isocyanide
- Isodesmosine
- Isodisomy
- Isoelectric focusing
- Isoelectric point
- Isoenzymes
- Isoetarine
- Isoferulic acid
- Isoflavones
- Isoflurane
- Isograft
- Isohumulone
- Isoinertial
- Isolated hepatic perfusion
- Isolated hypogonadotropic hypogonadism
- Isolation
- Isolation by distance
- Isolation chip
- Isolation ward
- Isoleucine
- Isoliquiritigenin
- Isomalt
- Isomaltase
- Isomaltose
- Isomer
- Isomerization
- Isometheptene
- Isometric exercise
- Isoniazid
- Isonicotinic acid
- Isopentenyl pyrophosphate
- Isopeptidase
- Isopeptide bonds
- Isophane insulin
- Isophorone
- Isophthalic acid
- Isopimaric acid
- Isopimpinellin