MIHAELA BOGDAN, LAURA ENDRES, BIANCA PASCA, DELIA MIRELA TIT, DIANA UIVAROSAN, DANA MARIA COPOLOVICI, LOTFI ALEYA, SIMONA BUNGAU STUDY ON THE STABILITY AND COMPATIBILITY OF THE COSMETIC PRODUCTS WITH LAVANDULA ANGUSTIFOLIA OIL KEPT IN PPH POLYPROPYLENE HOMOPOLYMER PLASTIC CONTAINERS The products used in cosmetic formulations are continuously diversifying as a result of researches in the field, which combine the healing and prevention of many skin conditions with the use of natural products such as vegetable extracts and essential oils. Testing the stability and compatibility of new or modified cosmetics is required to ensure that quality standards are met when stored in proper conditions for functionality and aesthetics, to preserve their chemical, microbiological and physical properties. In this study, the stability and compatibility of a new cosmetic product containing lavender essential oil in plastic container-plastic jar 100 mL PPH Polypropylene homopolymer (Moplen HP648T) is tested against the glass receptacle used as a control. The monitored parameters were organoleptic characteristics (appearance, color, fragrance), physicochemical (pH, density), under controlled temperature conditions, and the microbiological ones. The results of this study showed that the tested cosmetic product is compatible with the plastic container; data obtained were comparable with the organoleptic and physicochemical test results obtained in the case of the control sample stored at room conditions.