| Cloxazolam | 24166-13-0 | Anxiolytics | 1 |
| Clubmoss herb | | Herbal remedies | 1 |
| Coal Tar Solution | | | 1 |
| Coal Tar Topical Solution | | | 1 |
| Coal tar and zinc ointment | | | 1 |
| Cocamidopropyl betaine | 61789-40-0 | Dermatological Agents | 1 |
| Cocarboxylase Chloride | 67-52-7 | | 1 |
| Cocoa peels | | Herbal remedies | 1 |
| Codeine linctus | | | 1 |
| Colesevelam Hydrochloride | 182815-44-7 | | 1 |
| Colesevelam-Hydrochloride | 182815-44-7 | Bile acid sequestrants | 1 |
| Colestipol Hydrochloride | 37296-80-3 | | 1 |
| Collagenase clostridium histolyticum | 9001-12-1 | Enzyme Replacements/modifiers | 1 |
| Collodion 4% | 9004-70-0 | Dermatics | 1 |
| Colloidal Silver Solution | 9007-35-6 | Antimicrobial agents | 1 |
| Colloidal silica | 7631-86-9 | Disinfectants | 1 |
| Coltsfoot leaf | | Herbal remedies | 1 |
| Coluracetam | 1393477-72-9 | | 1 |
| Comfrey | | Herbal remedies | 1 |
| Common mallow flower | | Herbal remedies | 1 |
| Common thyme herb | | Herbal remedies | 1 |
| Condurango cortex | | Herbal remedies | 1 |
| Coneflower tincture | | Herbal remedies | 1 |
| Conestat alfa | 80295-38-1 | Hemostatics | 1 |
| Conjugated Estrogen | 12126-59-9 | | 1 |
| Copper (II) carbonate basic | 12069-69-1 | Minerals and electrolytes | 1 |
| Copper (II) oxide | 1317-38-0 | Minerals and electrolytes | 1 |
| Copper gluconate | 527-09-3 | | 1 |
| Copper tetraMIBI tetrafluoroborate | 103694-84-4 | | 1 |
| Copper(II) chloride dihydrate | 10125-13-0 | | 1 |
| Coriander | | Herbal remedies | 1 |
| Couch grass | | Herbal remedies | 1 |
| Cowslip flower | | Herbal remedies | 1 |
| CpG 1018 ODN | 112732-17-9 | Immunostimulants | 1 |
| CpG 7909 ODN | 2647530-73-0 | Immunostimulants | 1 |
| Crizotinib intermediates | 877399-74-1 | | 1 |
| Crospovidone (PVPP) | 9003-39-8 | | 1 |
| Cumin fruits powder | | Herbal remedies | 1 |
| Cumin seed | | Herbal remedies | 1 |
| Cupric Chloride | 7447-39-4 | Minerals and electrolytes | 1 |