Di(2-ethylhexyl) adipate (DEHA) is a widely used plasticizer and prevalent environmental contaminant. In this study, DEHA concentrations in the milk, cheese, and butter samples wrapped with food-grade commercial polyethylene films and stored at 4 °C for 30 days were detected using gas chromatographic analysis. Also, the effects of exposure to a high dose of DEHA for a long duration on the liver, brain, and heart of Wistar rats were assessed. Besides, the possible beneficial effect of Peganum harmala oil (PGO), in relieving DEHA induced adverse effects was explored. For this purpose, four groups (8 rats/group) were orally given physiological saline, PGO (320 mg/kg bwt), DEHA (2000 mg/kg bwt), or PGO + DEHA for 60 days. The results revealed that the DEHA concentrations in the tested dairy products were ordered as follows: (butter > cheese > milk). Notably, the detected levels in butter were higher than the specific migration limit in foods. DEHA induced a significant increase in the serum levels of glucose, alanine transaminase, aspartate transaminase, acetylcholine esterase, creatine kinase–myocardium bound, malondialdehyde, tumor necrosis factor-α, and interleukin-1β. But, significant hypoproteinemia, hypoalbuminemia, hypoglobulinemia, and hypocholesterolemia were evident following DEHA exposure. A significant reduction in the serum level of superoxide dismutase, reduced glutathione, and brain-derived neurotrophic factor was recorded. Besides, a significant downregulation in hepatic CYP2E1, brain glial fibrillary acidic protein, and cardiac troponin I gene expression was noticed. Moreover, DEHA exposure induced a significant decrease in Bcl-2 immunolabeling, but Caspase-3 immunoexpression was increased. On the contrary, PGO significantly recused DEHA injurious impacts. Therefore, PGO could represent a promising agent for preventing DEHA-induced hepatotoxicity, neurotoxicity, and cardiotoxicity