- Clobetasol
- Clobetasol propionate
- Clobetasone
- Clobetasone butyrate
- Clofarabine
- Clofazimine
- Clofibrate
- Clofibric acid
- Clomethiazole
- Clomifene
- Clomifene citrate
- Clomipramine
- Clonal anergy
- Clonal deletion
- Clonal evolution
- Clonal hematopoiesis
- Clonal interference
- Clonal population
- Clonal selection
- Clonal variation
- Clonality
- Clonazepam
- Clonazolam
- Clone
- Clonidine
- Cloning
- Cloning vector
- Clonogenic assay
- Clonorchiasis
- Clonorchis
- Clonorchis sinensis
- Clonus
- Clopidogrel
- Clorazepate
- Clorgiline
- Closed angle glaucoma
- Closed head injury
- Closed kinetic chain exercises
- Closed testing procedure
- Clostridia
- Clostridioides
- Clostridium
- Clostridium baratii
- Clostridium bifermentans
- Clostridium botulinum
- Clostridium butyricum
- Clostridium chauvoei
- Clostridium difficile
- Clostridium difficile infection
- Clostridium difficile toxin B
- Clostridium histolyticum
- Clostridium innocuum
- Clostridium novyi
- Clostridium perfringens
- Clostridium septicum
- Clostridium sporogenes
- Clostridium tertium
- Clostridium tetani
- Clostripain
- Clot formation
- Clot lysis time
- Clot retraction
- Cloth face masks
- Clothianidin
- Clotiapine
- Clotrimazole
- Clotting time
- Clouding of consciousness
- Clove
- Clove oil
- Cloves
- Cloves syndrome
- Cloxacillin
- Cloxazolam
- Clozapine
- Clozapine N oxide
- ClpX
- Club cells
- Clubfoot
- Clumping factor A
- Cluster B personality disorder
- Cluster B personality disorders
- Cluster analysis
- Cluster decay
- Cluster headaches
- Cluster of differentiation
- Cluster randomized trial
- Clusterin
- Clustering algorithms
- Clusters of differentiation
- Cluttering
- Cmin
- Co oximeter
- Co-dydramol
- Co-option
- Co-oximetry
- Co-receptors
- Co-rumination
- Co-sleeping
- Co-stimulation
- Coacervates
- Coacervation
- Coaching psychology
- Coactivation
- Coagulant
- Coagulase
- Coagulase negative staphylococci
- Coagulase negative staphylococcus
- Coagulase positive staphylococci
- Coagulation
- Coagulation cascade
- Coagulation factor IX
- Coagulation factor VII
- Coagulation factor VIII
- Coagulation factor X
- Coagulation factor XI
- Coagulation factor XII
- Coagulation factor XIII
- Coagulation screen
- Coagulation system
- Coagulation testing
- Coagulative necrosis
- Coagulin
- Coagulopathies
- Coagulopathy
- Coal dust
- Coal gas
- Coal oil
- Coal tar
- Coarctation of the aorta
- Coarse facial features
- Coarticulation
- Coats' disease
- Cobalamin
- Cobalt
- Cobalt 60
- Cobalt sulfate
- Cobalt-60
- Cobalt-chrome
- Cobamamide
- Cobb angle
- Cobblestone lissencephaly
- Cobimetinib
- Cobratoxin
- Coca
- Coca tea
- Cocaethylene
- Cocaine
- Cocaine and amphetamine regulated transcript
- Cocaine dependence