| Guanadrel | 40580-59-4 |
| Guanazodine | 32059-15-7 |
| Guanethidine | 55-65-2 |
| Guanidinoethylmercaptosuccinic acid | 77482-44-1 |
| Guanine | 73-40-5 |
| Guanoclor | 5001-32-1 |
| Guanosine 3'-monophosphate | 117-68-0 |
| Guanosine tetraphosphate | 33503-72-9 |
| Guanosine-2',3'-cyclophosphorothioate | 38557-85-6 |
| Guanosine-2'-monophosphate | 130-50-7 |
| Guanosine-5'-Diphosphate | 146-91-8 |
| Guanosine-5'-Monophosphate | 85-32-5 |
| Guanosine-5'-Triphosphate | 86-01-1 |
| Guanoxabenz | 24047-25-4 |
| Guanoxan | 2165-19-7 |
| Gunagratinib | 2211082-53-8 |
| Gusacitinib | 1425381-60-7 |
| Guselkumab | 1350289-85-8 |
| Gusperimus | 98629-43-7 |
| Guvacine | 498-96-4 |
| H3B-8800 | 1825302-42-8 |
| Hachimycin | 1394-02-1 |
| Hadacidin | |
| Hafnium oxide | 12055-23-1 |
| Halazepam | 23092-17-3 |
| Haletazole | 15599-36-7 |
| Halicin | 40045-50-9 |
| Halofantrine | 69756-53-2 |
| Halometasone | 50629-82-8 |
| Haloprogin | 777-11-7 |
| Haloxazolam | 59128-97-1 |
| Haloxon | 321-55-1 |
| Haloxyfop-P | 95977-29-0 |
| Harmine | 442-51-3 |
| Helium | 7440-59-7 |
| Hematin | 15489-90-4 |
| Hematoxylin | 517-28-2 |
| Heme arginate | 100438-92-4 |
| Hemicellulase | 9025-56-3 |
| Hemoglobin | 9008-02-0 |