Dry and powered oregano at concns. 0.5-2.5% by mass was added sep. to the oil and then the modified oil was stored at 10 degrees C for 7 and 14 days. The values of the acid no. (AN), peroxide no. (PN) and oxidn. induction times (OIT) of the modified oil samples were detd. after storage and compared with the corresponding values of the unmodified oil. The increase in the oregano content in the oil resulted in the increase of OIT and the redn. of AN and PN of the tested oils. The increase in storage period resulted in a decrease in AN value and in increase in the OIT value.