China 
Africa 
- Chronic renal insufficiency
- Chronic respiratory failure
- Chronic rhinosinusitis
- Chronic sclerosing sialadenitis
- Chronic scrotal pain
- Chronic sinusitis
- Chronic stress
- Chronic subjective dizziness
- Chronic suppurative otitis media
- Chronic tension headache
- Chronic thromboembolic pulmonary hypertension
- Chronic tonsillitis
- Chronic total occlusion
- Chronic toxicity
- Chronic urticaria
- Chronic venous insufficiency
- Chronic viral hepatitis
- Chronic wasting disease
- Chronic wounds
- Chronicity
- Chronobiology
- Chronobiotic
- Chronodisruption
- Chronotherapeutics
- Chronotherapy
- Chronotropic
- Chronotype
- Chrysanthemic acid
- Chrysanthemum
- Chrysanthemum morifolium
- Chryseobacterium
- Chryseobacterium indologenes
- Chrysiasis
- Chrysin
- Chrysoeriol
- Chrysolaminarin
- Chrysophanic acid
- Chrysopogon zizanioides
- Chrysosporium
- Chrysotile
- Chunking
- Churg Strauss Syndrome
- Churg-Strauss syndrome
- Churna
- Chvostek sign
- Chyle
- Chylomicron retention disease
- Chylomicronemia
- Chylomicrons
- Chylothorax
- Chylous ascites
- Chyluria
- Chymase
- Chyme
- Chymopapain
- Chymotrypsin
- Chymotrypsin C
- Chymotrypsinogen
- Chytridiomycosis
- Ci protein
- Cib1
- Cibotium
- Cicatricial alopecia
- Cicatricial pemphigoid
- Cicer
- Ciclesonide
- Cicletanine
- Ciclopirox
- Ciclopiroxolamine
- Ciclosporin
- Cicutoxin
- Cidex
- Cidofovir
- Cigar smoking
- Cigarette smoking
- Cigarette smoking for weight loss
- Ciglitazone
- Ciguatera
- Ciguatoxin
- Cilansetron
- Cilantro
- Cilazapril
- Cilengitide
- Cilia
- Ciliary arteries
- Ciliary artery
- Ciliary body
- Ciliary ganglion
- Ciliary muscle
- Ciliary neurotrophic factor
- Ciliary process
- Ciliary processes
- Ciliogenesis
- Ciliopathies
- Ciliopathy
- Cilnidipine
- Cilofungin
- Cilomilast
- Cilostazol
- Cimetidine
- Cimino fistula
- Cinacalcet
- Cinchocaine
- Cinchona
- Cinchona alkaloid
- Cinchona officinalis
- Cinchona pubescens
- Cinchonine
- Cinchonism
- Cincinnati Prehospital Stroke Scale
- Cineangiography
- Cinemeducation
- Cineole
- Cineradiography
- Cingulate cortex
- Cingulate gyrus
- Cingulate sulcus
- Cingulotomy
- Cingulum
- Cinitapride
- Cinnabar
- Cinnamaldehyde
- Cinnamates
- Cinnamic acid
- Cinnamomum camphora
- Cinnamomum cassia
- Cinnamomum tamala
- Cinnamon
- Cinnamycin
- Cinnamyl acetate
- Cinnamyl alcohol
- Cinnarizine
- Cinoxacin
- Cinoxate
- Cipargamin
- Ciprofloxacin
- Ciproxifan
- Ciraparantag
- Circadian rhythm
- Circadian rhythm sleep disorder
- Circadian rhythm sleep disorders
- Circadian rhythms
- Circle of Friends
- Circle of Willis
- Circovirus
- Circuit training
- Circular RNA
- Circular dichroism
- Circular dichroism spectroscopy
- Circular folds