| Record No. | Name | No. of Entries |
| 401 | Hydroxymethyl colchicine | 1 |
| 402 | Ipecoside | 1 |
| 403 | Ircodin | 1 |
| 404 | Isoapocodeine | 1 |
| 405 | Isoapocodeine hydrochloride | 1 |
| 406 | Isoapomorphine | 1 |
| 407 | Isochondrodendrine,(-,-)- | 1 |
| 408 | Isococculidine | 1 |
| 409 | Isocorydine | 94 |
| 410 | Isocorydine hydrochloride | 1 |
| 411 | Isocorypalmine | 10 |
| 412 | Isofagaridine | 1 |
| 413 | Isopavine | 1 |
| 414 | Isoteolin | 44 |
| 415 | Isothebaine | 8 |
| 416 | Isothebaine hydrochloride | 1 |
| 417 | Isotrilobine-N-2-oxide | 1 |
| 418 | Jatrorrhizine | 21 |
| 419 | Kadil | 1 |
| 420 | Kreysiginone | 1 |
| 421 | Kyoberin | 1 |
| 422 | L-CSLMS | 2 |
| 423 | Laudanosine | 1 |
| 424 | Laurifine | 1 |
| 425 | Laurifoline | 1 |