- 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