Oxysterols (oxidised cholesterol) may play a role in the pathogenesis of Similar to cholesterol, plant sterols are susceptible to oxidation. is known about the potential atherogenicity of oxidised plant sterols (oxyphytosterols). In the present study, the atherogenicity of a mixture oxyphytosterols was examined by feeding female LDL receptor-deficient mice for 35 weeks a control diet (atherogenic high-fat diet; n 9), an diet (control diet+0.025 % (w/w) oxysterols; n 12) or an oxyphytosterol (control diet+0.025 % (w/w) oxyphytosterols; n 12). In the LDLR+/ - levels of cholesterol, lipoprotein profiles, cholesterol exposure and inflammatory markers at the end of the experiment were comparable three diet groups. Nevertheless, the proportion of severe was significantly higher after oxysterol (41 %; P= 0.004) and %; P= 0.011) diet consumption than after control diet consumption (26 Oxyphytosterol levels in the lesions were the highest in the group. Here, we show that not only dietary oxysterols but also dietary oxyphytosterols increase the proportion of severe atherosclerotic suggests that plant sterols when oxidised may increase atherosclerotic severity instead of lowering the size and severity of lesions when fed non-oxidised form. Therefore, this finding might give an indication as to find the answer in the current hot debate about the potential of plant sterols. However, to what extent these results can be the human situation warrants further investigation.