- ITGB3
- ITK
- ITK-SNAP
- ITPR2
- IUDs
- IV
- IVF
- IVIVC
- IVM
- Iatrogenesis
- Iatrogenic anemia
- Iatrogenic disease
- Ibalizumab
- Ibandronic acid
- Iberogast
- Iboga
- Ibogaine
- Ibopamine
- Ibotenic acid
- Ibritumomab tiuxetan
- Ibrutinib
- Ibuprofen
- Icaridin
- Icariin
- Icatibant
- Ice baths
- Ichor
- Ichthyol
- Ichthyosis
- Ichthyosis linearis circumflexa
- Ichthyosis prematurity syndrome
- Ichthyosis vulgaris
- Icilin
- Iclaprim
- Icodextrin
- Iconic memory
- Icoslg
- Icotinib
- Ictal
- Ictal bradycardia
- Id reaction
- Idarubicin
- Idarucizumab
- Idazoxan
- Idea
- Ideal body weight
- Ideal electrode
- Ideas and delusions of reference
- Ideation
- Ideational apraxia
- Idebenone
- Idelalisib
- Identification
- Identification with the Aggressor
- Identity by descent
- Identity crisis
- Identity development
- Identity disorder
- Identity formation
- Ideomotor apraxia
- Idiopathic CD4+ lymphocytopenia
- Idiopathic chronic fatigue
- Idiopathic generalized epilepsy
- Idiopathic hypersomnia
- Idiopathic inflammatory myopathies
- Idiopathic interstitial pneumonia
- Idiopathic intracranial hypertension
- Idiopathic orbital inflammatory disease
- Idiopathic pneumonia syndrome
- Idiopathic pulmonary fibrosis
- 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