China 
Africa 
- Anaphase promoting complex
- Anaphase-promoting complex
- Anaphylactoid purpura
- Anaphylatoxins
- Anaphylaxis
- Anaplasia
- Anaplasma
- Anaplasma phagocytophilum
- Anaplasmosis
- Anaplastic astrocytoma
- Anaplastic carcinoma
- Anaplastic lymphoma kinase
- Anaplastic oligodendroglioma
- Anaplastic thyroid cancer
- Anaplerotic reactions
- Anasarca
- Anastomosis
- Anastrozole
- Anatabine
- Anatomical Therapeutic Chemical Classification System
- Anatomical model
- Anatomical pathology
- Anatomical snuffbox
- Anatomical terminology
- Anatomical variation
- Anatomy
- Anatoxin-a
- Ancestry
- Anchor test
- Anchorage
- Anchoring effect
- Anchoring fibrils
- Ancient DNA
- Ancient protein
- Anconeus
- Anconeus muscle
- Ancrod
- Ancylostoma caninum
- Ancylostoma duodenale
- Ancylostomiasis
- Andarine
- Andersen-Tawil Syndrome
- Andersen-Tawil syndrome
- Anderson-Darling test
- Andes virus
- Andexanet alfa
- Androgen binding protein
- Androgen deficiency
- Androgen deprivation
- Androgen deprivation therapy
- Androgen insensitivity syndrome
- Androgen receptor
- Androgen receptor antagonist
- Androgen suppression
- Androgen-binding protein
- Androgenic alopecia
- Androgens
- Andrographis paniculata
- Andrographolide
- Android fat distribution
- Andrologist
- Andrology
- Andropause
- Androstadienone
- Androstane
- Androstanediol
- Androstanolone
- Androstenediol
- Androstenedione
- Androsterone
- Anechoic chamber
- Anecortave
- Anejaculation
- Anelloviridae
- Anemia
- Anemia in pregnancy
- Anemia of chronic disease
- Anemia of prematurity
- Anemonin
- Anencephalus
- Anencephaly
- Anergy
- Anesthesia
- Anesthesiology
- Anesthetic agents
- Anesthetics
- Anestrus
- Anethole
- Anetoderma
- Aneuploidy
- Aneurysm
- Aneurysmal bone cyst
- Angelica
- Angelica acutiloba
- Angelica archangelica
- Angelica dahurica
- Angelica gigas
- Angelica root
- Angelica sinensis
- Angelicin
- Angelman syndrome
- Anger
- Anger management
- Angina
- Angina pectoris
- Angioblasts
- Angiodysplasia
- Angioedema
- Angiofibroma
- Angiogenesis
- Angiogenesis inhibitors
- Angiogenin
- Angiography
- Angioid streaks
- Angioimmunoblastic T-cell lymphoma
- Angiokeratoma
- Angioleiomyoma
- Angiolipomas
- Angiology
- Angiomas
- Angiomatoid fibrous histiocytoma
- Angiomatosis
- Angiomyolipomas
- Angiomyxoma
- Angiopathy
- Angioplasty
- Angiopoietin
- Angiopoietin 1
- Angiopoietin 2
- Angiopoietin receptor
- Angiopoietin-2
- Angiosarcoma
- Angioscope
- Angioscopy
- Angiosome
- Angiostatin
- Angiostrongyliasis
- Angiostrongylus cantonensis
- Angiotensin
- Angiotensin I
- Angiotensin II
- Angiotensin II receptor antagonists
- Angiotensin II receptor type 1
- Angiotensin III
- Angiotensin converting enzyme
- Angiotensin receptor
- Angiotensin-converting enzyme
- Angiotensinogen
- Angle of His
- Angle of incidence