| Co [ a - z ] | Nummer |
| Cobalt | 12 / 18 / 19 / # (19a+c) |
| Cobalt-(II)-acetat Tetrahydrat | 12 / 18 / 19a+b / # (19c) |
| Cobalt-benzolsulfonat | 14 / 12 / 18 / 19 / # (19a) |
| Cobalt-carbonat | 12 / 18 / 19a+b / # (19c) |
| Cobalt-(II)-chlorid | 14 / 12 / 16 / 18 / 19 / 19b 19a - # 220 / # (19c) |
| Cobalt-(II)-chlorid Hexahydrat | 14 / 12 / 16 / 18 / 19 / 19a - # 220 |
| Cobalt-di-chlorid | 14 / 12 / 16 / 18 / 19 / 19b 19a - # 220 / # (19c) |
| Cobalt-(II)-nitrat Hexahydrat | 14 / 12 / 13 / 16 / 18 / 19 19a+b / # (19c) |
| Cobaltoctacarbonyl | 14 / 12 / 18 / 19 |
| Cobaltoxid | 12 / 18 / 19a / # (19c) |
| Cobalt-(II)-sulfat | 14 / 12 / 18 / 19 / 19a - # 220 |
| Cobalt-(II)–sulfat Heptahydrat | 14 / 12 / 18 / 19 / 19b 19a - # 220 / # (19c) |
| Cobaltsulfid | 12 / 18 / 19 / # (19a+c) |
| Cobalt-Verbindungen | 12 / 18 / # (19a+c) |
| Cocain »Online!« | 14 / # 229 Info |
| d-Cocain | 14 |
| Cochenillerot A | 16 |
| Cocobolo | 18 |
| Cocusholz | |
| Codein | 14 / 18 / # 230 Info |
| Codein-N-oxid | 14 / # 230 Info |
| Codeinphosphat-Hemihydrat | 14 |
| Codiaeum variegatum pictum | 18 |
| Codoxim | 14 |
| Coffea arabica | |
| Coffearin | |
| Coffein | 14 / # (19c) |
| Cola acuminata | 14 |
| Colcemid | 14 / 16 / # (19c) |
| Colchicin | 14 / 16 / # (19c) / »Tödlich(!)« |
| Colchicosid | 16 |
| Colchicum autumnale | 14 / 16 |
| Colestyramin | xxx |
| Coleus–Blumei-Hybriden | 16 |
| Collman’s Reagens | xxx |
| Colophonium | 18 |
| Colutea arborescens | 16 |
| Concanavalin A | 14 |
| Condurango | 16 |
| Conessin | |
| Coniferylbenzoate | 16 / selten 18 |
| D L - Coniin | xxx |
| Coniin | 14 |
| Conium maculatum | |
| Consolida regalis | 16 |
| Convalla-marogenin | 14 |
| Convallaria-majalis | |
| Convalla-toxin | |
| Convolvamin | |
| Conyrin | |
| Coomassie Brillant blue G 250 | 16 |
| Coomassie Brillant blue R 250 | |
| Copaifera reticulata | |
| Copaifera reticulata | 14 / # 56 Alkohol |
| Coprin | xxx |
| Coprinus atramentarius | # 56 Alkohol |
| (-)-Coralynchlorid Hydrat | 14 |
| Corazol | 8 |
| Coriaria myrtifolia | 16 |
| Cornus sanguinea | |
| Coronilla varia | |
| Coroxon | 14 |
| Cortinarius gentilis | # 227 H |
| Cortinarius orellanus | 14 / 9 |
| Cortinarius speciosissimus | |
| Cortinarius splendens | 14 / 15 |
| Cortinarius traganus | 16 |
| Cortison | xxx |
| Corydalis cava | 14 |
| Corynanthin | |
| D L - Corypalmin | |
| Costunolid | Selten 18 |
| Costus | 18 |
| Costuswurzelöl | |
| Cotinin | 14 |
| Cotinus coggygria | # 227 H |
| Cotoneaster-Medicus-Arten | 7 / # 227 (+) |
| Co-Trimoxazol | xxx |
| Cotyledon orbiculata | # 227 ++ |
| Coumachlor | 3a / 18 |
| Coumafuryl | 14 |
| Coumaphos | 14 / 19 |
| Coumatetralyl | |
| Coumetarol | 16 |
| Coumithoat | 4 / 19 |