China 
Africa 
- Identity development
- Identity disorder
- Identity formation
- Ideomotor apraxia
- Idiopathic CD4+ lymphocytopenia
- Idiopathic chronic fatigue
- Idiopathic generalized epilepsy
- Idiopathic guttate hypomelanosis
- Idiopathic hypersomnia
- Idiopathic inflammatory myopathies
- Idiopathic interstitial pneumonia
- Idiopathic intracranial hypertension
- Idiopathic orbital inflammatory disease
- Idiopathic pneumonia syndrome
- Idiopathic pulmonary fibrosis
- Idiopathic pulmonary haemosiderosis
- Idiopathic short stature
- Idiopathic thrombocytopenic purpura
- Idiosyncratic drug reactions
- Idiothetic
- Idiotype
- Idioventricular rhythm
- Idoxuridine
- Idraparinux
- Iduronate-2-sulfatase
- Iduronidase
- Idursulfase
- Ifenprodil
- Ifetroban
- Ifi202
- Ifosfamide
- IgA
- IgA deficiency
- IgA nephropathy
- IgA pemphigus
- IgA1 protease
- IgG deficiency
- IgG4-related disease
- IgM
- Igmesine
- Ikigai
- Ikzf1
- Ikzf3
- Il2rg
- Ilaprazole
- Ileal conduit
- Ileitis
- Ileo anal pouch
- Ileocecal valve
- Ileocolic artery
- Ileostomy
- Ileum
- Ileus
- Ilex paraguariensis
- Iliac artery
- Iliac crest
- Iliac fascia
- Iliac fossa
- Iliac spine
- Iliacus
- Iliacus muscle
- Iliocostalis
- Iliofemoral ligament
- Iliohypogastric nerve
- Ilioinguinal nerve
- Iliolumbar artery
- Iliolumbar ligament
- Iliopsoas
- Iliopsoas muscle
- Iliopubic eminence
- Iliopubic tract
- Iliotibial band
- Iliotibial band syndrome
- Iliotibial tract
- Ilium
- Illegal abortion
- Illegitimate recombination
- Illicium verum
- Illite
- Illusion of control
- Illusion of transparency
- Illusory correlation
- Iloperidone
- Iloprost
- Image
- Image intensifiers
- Image registration
- Image-guided radiation therapy
- Image-guided surgery
- Imagery rescripting
- Imaginary audience
- Imagination
- Imaging
- Imaging biomarkers
- Imaging genetics
- Imaging informatics
- Imaging phantom
- Imatinib
- Imazaquin
- Imbibition
- Imetelstat
- Imidapril
- Imidazolate
- Imidazole
- Imidazolidine
- Imidazolidinone
- Imidazolidinyl urea
- Imidazoline
- Imidazoline receptor
- Imidazoline receptors
- Imidazoquinoline
- Imidazothiazoles
- Imide
- Imidocarb
- Imiglucerase
- Imines
- Iminodiacetic acid
- Iminosugars
- Imipenem
- Imipenem cilastatin
- Imipramine
- Imiquimod
- Imitation
- Immediate early gene
- Immediate hypersensitivity
- Immersion foot
- Immobilization
- Immobilized enzymes
- Immortalised cell line
- Immortality
- Immune adherence
- Immune checkpoint
- Immune complexes
- Immune disorders
- Immune dysregulation
- Immune electron microscopy
- Immune evasion
- Immune function
- Immune privilege
- Immune receptors
- Immune repertoire
- Immune system
- Immune thrombocytopenic purpura
- Immune tolerance
- Immune tolerance in pregnancy
- Immune-mediated inflammatory diseases
- Immune-related response criteria
- Immunity
- Immunization
- Immunization registry