| Obeticholic Acid | 459789-99-2 | | 1 |
| Octisalate | | | 1 |
| Octocrylene | | | 1 |
| Oflea-wort seed | | Herbal remedies | 1 |
| Olaparib intermediates | 218301-22-5 | | 1 |
| Olive tree leaf cut | | Herbal remedies | 1 |
| Olodaterol | 868049-49-4 | Adrenergic agents | 1 |
| Omadacycline | 389139-89-3 | Tetracyclines | 1 |
| Omalizumab | 242138-07-4 | Immunosuppressants | 1 |
| Omega-3 Acid Ethyl Ester 90 | 99685-96-8 | Other therapeutic nutrients/minerals/electrolyte | 1 |
| Omega-3-acid ethyl esters 60 | | Lipid-lowering agents | 1 |
| Ondansetron Compound A | 119812-29-2 | 5HT3 antagonists | 1 |
| Orange petals | | Herbal remedies | 1 |
| Orris root | | Herbal remedies | 1 |
| Orthodichlorobenzene | 95-50-1 | Disinfectants | 1 |
| Osimertinib intermediates | 142-25-6 | | 1 |
| Oteseconazole | 1340593-59-0 | Antimycotics | 1 |
| Otilonium | 105360-89-2 | Antispasmodics | 1 |
| Oxalate salt of Benzyl (2S,5R)-5-((Benzyloxy)amino)piperidine
-2-carboxylate | 1171080-45-7 | Intermediates | 1 |
| Oxerutin | 17673-25-5 | | 1 |
| Oxolamine Citrate | 83886-84-6 | Antitussives | 1 |
| Oxolinic Acid | 14698-29-4 | Quinolones | 1 |
| Oxytetracycline Hydrochloride | 2058-46-0 | | 1 |
| Ozagrel sodium | 189224-26-8 | | 1 |
| Ozanimod | 1306760-87-1 | | 1 |
| Ozenoxacin | 245765-41-7 | | 1 |
| Ozenoxacin Intermediates | | | 1 |
| Paize | | Antispasmodics | 1 |
| Palbociclib intermediates | 733039-20-8 | | 1 |
| Pale coneflower root | 84929-31-7 | Herbal remedies | 1 |
| Palladium Chloride | 2864-50-8 | | 1 |
| Palm tree leaves | | Herbal remedies | 1 |
| Palmitic Acid | 57-10-3 | Dermatics | 1 |
| Palmitoyl Oligopeptide | 5987-82-6 | | 1 |
| Palmitoyl Tripeptide | 1-147732-56-7 | | 1 |
| Panax Ginseng dry extract 10% | 50647-08-0 | Herbal remedies | 1 |
| Pancrelipase | 53608-75-6 | Pancreatic enzymes | 1 |
| Pantethine | 16816-67-4 | Dietary supplements | 1 |
| p-Dimethylaminophenole Hydrochloride | | Analgesics | 1 |
| pancreatin | 8049-47-6 | | 1 |