| Ibrutinib, [Carbonyl-14C]- | MC 2699 |
| Ibudilast, [3H]- | MT 2039 |
| Icaritin, [3-methyl-2-butenyl-1-14C]- | MC 2789 |
| Idarubicin, [14C]- | MC 1002882 |
| Imazalil, [dichlorophenyl ring-14C(U)]- | MC 2418 |
| Imazalil sulfate, [dichlorophenyl ring-14C(U)]- | MC 2449 |
| Imazamox, [imidazolin-14C]- | MC 2628 |
| Imidacloprid, [imidazole-2-14C]- | MC 2528 |
| Imidazole, [2-14C]- | MC 2233 |
| Imiquimod | M 1822 |
| Imiquimod, [3H]- | MT 1842 |
| Imperatorin, [3H]- | MT 2062 |
| Indole, [2-14C]- | MC 456 |
| Indole-3-butyric acid, [indole-2-14C]- | MC 2461 |
| Indoxyl sulfate, potassium salt, [3H]- | MT 1751 |
| Ink, [14C]- red | MC 229 |
| β-L-Inosine | M 1807 |
| β-L-Inosine, [8-3H(N)]- | MT 1829 |
| Inosine, [14C(U)]- Discontinued | MC 171 |
| Inosine, [8-14C]- | MC 148 |
| Inosine, [2,8-3H]- | MT 678 |
| Inosine 5'-monophosphate, diammonium salt, [8-14C]- | MC 192 |
| Inosine 5'-monophosphate, diammonium salt, [8-3H]- | MT 999 |
| D-allo-Inositol, [3H]- Discontinued | MT 1675 |
| D-chiro-Inositol, [3-3H]- Discontinued | MT 1645 |
| myo-Inositol, [2-3H]- | MT 916 |
| Inulin carboxyl, [carboxyl-14C]- Discontinued | MC 1464 |
| Inulin methoxy, [methoxy-14C]- | MC 1465 |
| Iodoacetic acid, [1-14C]- | MC 1127 |
| 6-Iodo-2-aminopurine, [8-14C]- | MC 2007 |
| 5-Iodocytidine | M 1794 |
| 5-Iodo-2'-deoxycytidine | M 1757 |
| 5-Iodo-2'-deoxyuridine | M 1756 |
| 5-Iodo 2'-deoxyuridine, [6-14C]- | MC 1108 |
| 5-Iodo 2'-deoxyuridine, [6-3H]- | MT 679 |
| 5-Iodo 2'-deoxyuridine 5'-monophosphate, diammonium salt, [6-3H]- | MT 758 |
| 5-Iodo-2'-deoxyzebularine, [5'-3H]- | MT 1739 |
| 6-Iodoguanine, [8-14C]- | MC 2007 |
| 5-Iodouracil, [2-14C]- | MC 315 |
| 5-Iodouracil, [6-3H]- | MT 627 |
| 5-Iodouracil dioxolane, [5'-3H]- | MT 1659 |
| 5-Iodouridine | M 1795 |
| Ioxynil, [ring-14C(U)]- | MC 2347 |
| Ioxynil octanoate, [ring-14C(U)]- | MC 2349 |
| Iperoxo, [methyl-3H]- | MT 1987 |
| 4-Ipomeanol, [3H]- | MT 803 |
| Ipratropium bromide, [3H]- | MT 2056 |
| Irbesartan, [3H]- | MT 2176 |
| Iressa, [3H]- | MT 1979 |
| Irgarol, [ring-14C(U)]- | MC 2161 |
| Isethionic acid amide, [13C2, 15N1]- | MG 159 |
| Isobutyric acid, sodium salt, [1-14C]- | MC 2022 |
| Isobutyric acid, sodium salt, [1-14C]- | MC 2022L |
| Isobutyric acid, [2-14C]- | MC 452 |
| Isoeugenol, [ring-14C(U)]- | MC 2128 |
| Isoeugenol, [3H]- | MT 1962 |
| L-Isoleucine, [14C(U)]- | MC 174 |
| L-Isoleucine, [3H]- | MT 2189 |
| N-FMOC-L-Isoleucine, [1-14C]- | MC2744 |
| L-alloIsoleucine, [3H]- | MT 1788 |
| Isoniazid, [carbonyl-14C]- | MC 448 |
| Isonicotinic acid, [carboxyl-14C]- | MC 2027 |
| Isonicotinic acid N-oxide, [carboxy-14C]- | MC 2089 |
| Isoorotic acid, [carbonyl-14C]- | MC 2042 |
| Isopentenol, [1-3H]- | MT 1636 |
| Isopentyl nitrite, [1-14C]- | MC 2742 |
| Isophthalic acid, [ring-14C(U)]- | MC 2179 |
| Isopropanol, [2-14C]- | MC 1161 |
| Isopropanol, [2-14C]- | MC 1161H |
| Isopropanol, [3H]- | MT 1948 |
| cis,trans-4-(isopropyl)cyclohexanemethanol, [methanol-14C]- | MC 2566 |
| Isopropyl myristate, [1-14C]- | MC 1410 |
| 2-Isopropyl-N,2,3-trimethylbutanamide, [carbonyl-14C]- | MC 2793 |
| 4-Isopropylphenylacetaldehyde, [14C=O]- | MC 2457 |
| Isopulegol, [hydroxymethyl-14C]- | MC 2613 |
| Isosorbide, [14C(U)]- | MC 2543 |
| Itraconazole, [3H]- | MT 1943 |
| Ivacaftor, [3H]- | MT 2088 |
| Ivermectin B1a, [22,23-3H]- | MT 2076 |