Interest in medicinal plants has burgeoned due to the increased efficiency of new plant-derived drugs and the growing interest in natural products. Because of the concerns about the side effects of conventional medicine, the use of natural products as an alternative to conventional treatment in healing and treatment of various diseases has been on the rise in the last few decades. The use of plants as medicines dates from the earliest years of man's evolution. Medicinal plants serve as therapeutic alternatives, safer choices. A larger number of these plants and their isolated constituents have shown beneficial therapeutic effects so we worked this study todetermine the effect ofdifferent levels ofnigella sativa onbiochemicalchanges on hypercholesterolemic rats. Twenty eight white Albino rats were divided into two main groups first set of mice infected with hypercholesterolemic, Second group of negative control, a non-mice group infected and was then the first and second main group is divided into seven sub-groups, including five groups fed with different concentrations of (5%, 10%, 15% ,20% and 25%) nigella sativa and one group control positive infected with the disease do not feed on the experimental diet and another control negative non-infected this disease means that all mice are divided into seven groups of four mice in each group. The results showed the best effect recorded for 20% nigella sativa which this treatment corrected completely the rise of GOT activity which was even less than control (-ve) group ,at the same time highest decrease of T. cholesterol was recorded for 10% nigella sativa also lowest LDL was recorded for (10% nigella sativa. which maximum decrease in T. lipids was found for 15% of nigella sativa. Best result in phospholipids may be that of 15%, nigella sativa diet, maximum increase of HDL was found for (15%) nigella sativa diet.