The objective of this study was to prepare a nanoemulsion of apple seed oil and investigate its biological effects on cancerous and normal cell lines, as well as to study its efficacy in curing experimentally induced dermatitis in rats. Apple seed oil nanoemulsion was prepared through a mechanical emulsification method along with ultrasonic waves, employing a formulation containing 5% apple seed oil along with Tween 80 and glycerol as cofactors. The chemical constituents of apple seed oil were identified through gas chromatography-mass spectrometry (GC-MS), wherein 22 chemical compounds were identified, of which 10E,12Z-octadecadienoic acid and oleic acid. Physical properties indicated that the nanoemulsion is stable during storage, as the size of the particles varied between 40-100 nm, along with a zeta potential of -35 mV. Cytotoxicity was assessed using the MTT assay on the A431 melanoma cell line and the Vero normal cell line. The results showed that the nanoemulsion possesses a concentration-dependent inhibitory effect on cancer cell growth, with cancer cell viability 80% significantly reduced at high concentrations, while its effect on normal cells was relatively limited 20%. The therapeutic effect of the nanoemulsion-containing gel was also evaluated in a formalin-induced dermatitis model in rats. Histological examinations revealed a significant improvement in skin structure and a reduction in inflammatory infiltration and hyperkeratosis compared to the untreated group. These results indicate that the apple seed oil nanoemulsion possesses anti-inflammatory and anticancer properties with a good degree of biosafety, making it a promising candidate for future pharmaceutical and dermatological applications.