| 35250 | Oxytetracycline hydrochloride (INNM), not put up as medicaments | |
| 35250 | Oxytocin (INN), not put up as medicaments | |
| 01219 | Oyster plant, fresh or chilled | |
| 21399 | Oyster plant, prepared or preserved other than by vinegar or acetic acid, frozen or not | |
| 21319 | Oyster plant, uncooked or cooked by steaming or boiling in water, frozen | |
| 04220 | Oysters, fresh, chilled, frozen, salted or in brine | |
| 21261 | Oysters, frozen, dried, salted or in brine | |
| 21280 | Oysters, prepared or preserved, not simply frozen, dried, salted or in brine, whether or not in airtight containers | |
| 21280 | Oysters, smoked | |
| 35332 | Ozokerite mixed with animal, vegetable or artificial waxes, not emulsified or containing solvents | |
| 33500 | Ozokerite, crude or refined, not chemically modified | |
| 34210 | Ozone | |
| 48160 | Ozone therapy apparatus | |
| 46939 | Ozone-generating and diffusing appliances, electrical, designed for non-therapeutic purposes | |