Forty-two healthy male albino rabbits weighing around 1 Kg were divided into 4 groups. Group I (8)- fed on normal stock diet, Group II (8)- fed on stock diet plus cholesterol (0.5 gm in 5 ml of olive oil). Group III (15)- received stock diet plus cholesterol plus garlic (0.25 gm) juice. Group IV (11)- received stock diet plus cholesterol plus onion (2.5 gm) juice. The animals were closely observed and followed for 16 weeks. Approximately every 4 weeks, blood samples were collected for estimation of various parameters (S. cholesterol, S. triglycerides, S. lipoproteins, S. phospolipids, and fibrinolytic activity). At the end of experiment, animals were sacrificed and degree of aortic atherosclerosis was graded (grade 0 to 4) in different groups and compared. Experimental study revealed that both garlic and onion (garlic more than onion) had significant effect in inhibiting the rise in S. cholesterol, S. triglycerides, S. beta lipoproteins, and S. phospolipids and significant effect in enhancing the fibrinolytic activity. The beta: alpha ratio was altered favourably and the ratio was kept close to normal. As regards the degree of aortic atherosclerosis as seen on post mortem, it was significantly less in garlic and onion group when compared with pure cholesterol group.