China 
Africa 
- Circulating endothelial cells
- Circulating free DNA
- Circulating tumor DNA
- Circulating tumor cells
- Circulation
- Circulatory system
- Circumcision
- Circumflex scapular artery
- Circumoral paresthesia
- Circumsporozoite protein
- Circumstantial speech
- Circumventricular organs
- Cirrhosis
- Cirsoid aneurysm
- Cis acting element
- Cis isomer
- Cis-2-Decenoic acid
- Cisapride
- Cisatracurium
- Cisplatin
- Cissampelos
- Cissampelos pareira
- Cissus
- Cistanche
- Cistanche deserticola
- Cisterna
- Cisterna chyli
- Cisterna magna
- Cistron
- Citalopram
- Citicoline
- Citraconic acid
- Citral
- Citrate
- Citrate synthase
- Citrates
- Citric acid
- Citric acid cycle
- Citrinin
- Citrobacter
- Citrobacter koseri
- Citron
- Citronella oil
- Citronellal
- Citronellol
- Citropten
- Citrullination
- Citrulline
- Citrullinemia
- Citrullinemia type I
- Citrullus colocynthis
- Citrus aurantium
- Citrus medica
- Civet
- Civility
- Clades
- Cladinose
- Cladistics
- Cladogram
- Cladosporium
- Cladribine
- Clanging
- Clara cells
- Clarithromycin
- Clark level
- Clark's level
- Clarke's nucleus
- Claspers
- Class II bacteriocins
- Class III β-tubulin
- Class switch recombination
- Classic autism
- Classic galactosemia
- Classical Hodgkin lymphoma
- Classical complement pathway
- Classical conditioning
- Classical genetics
- Classical pathway
- Classical pharmacology
- Classical swine fever virus
- Classical test theory
- Classification
- Classification of obesity
- Clastogen
- Clastogenic
- Clathrate
- Clathrin
- Clathrin coated vesicles
- Clathrin-coated vesicles
- Claude's syndrome
- Claudication
- Claudin
- Claustrophobia
- Claustrum
- Claviceps
- Claviceps purpurea
- Clavicle
- Clavicle fracture
- Clavipectoral fascia
- Clavulanate potassium
- Clavulanic acid
- Clazosentan
- Clean Air Act
- Cleanser
- Clear cell
- Clear cell acanthoma
- Clear cell carcinoma
- Clear cell renal cell carcinoma
- Clear cell sarcoma
- Clear cell sarcoma of the kidney
- Clear-cell adenocarcinoma
- Clear-cell sarcoma
- Clear-cell sarcoma of the kidney
- Clearance
- Clearing the cervical spine
- Cleavage and polyadenylation specificity factor
- Cleavage furrow
- Clebopride
- Clec7a
- Cleft
- Cleft lip
- Cleft lip and palate
- Cleft lip with or without cleft palate
- Cleft palate
- Cleidocranial dysplasia
- Clemastine
- Clemizole
- Clenbuterol
- Clerodane diterpene
- Clevidipine
- Clevudine
- Clic2
- Clic6
- Client-centered therapy
- Climate change mitigation
- Climate psychology
- Climbazole
- Climbing fibers
- ClinVar
- Clindamycin
- Clindamycin phosphate
- Cline
- Clinical Associate
- Clinical Commissioning Groups
- Clinical Opiate Withdrawal Scale
- Clinical Trials Directive
- Clinical attachment loss
- Clinical biochemistry
- Clinical clerkships
- Clinical collaboration