| Record No. | Name | No. of Entries |
| 176 | Buprenorphine-d4 | 1 |
| 177 | Buprenorphine-O3-glucuronide | 1 |
| 178 | Butorphanol | 1 |
| 179 | C-Alkaloid G | 1 |
| 180 | C-Curarine | 10 |
| 181 | C-Toxiferine 1 | 2 |
| 182 | Caffeine | 18 |
| 183 | Calebassine | 1 |
| 184 | Canadine | 1 |
| 185 | Capaurine | 7 |
| 186 | Carbethoxy reticuline | 1 |
| 187 | Caryachine | 1 |
| 188 | Cavidine | 1 |
| 189 | CCRIS 3820 | 1 |
| 190 | Cephaelin | 30 |
| 191 | Cephalotaxine | 1 |
| 192 | Cepharadione A | 1 |
| 193 | Cepharanthine | 3 |
| 194 | Chelirubine | 4 |
| 195 | Chlorcolchicine | 1 |
| 196 | Chlorocodeine | 1 |
| 197 | Chloroethylnorapomorphine | 1 |
| 198 | Chondocurine | 1 |
| 199 | CID10124998 | 1 |
| 200 | CID10148913 | 1 |