Objective: To study the prevention of the development of fatty liver by garlic. Materials and methods: Fatty liver models were induced by chronically feeding rats a high fat diet containing 10% lard. The rats were injected with carbon tetrachloride, and then liver pathology was confirmed by hematoxylin-eosin stain. In addition to the rats of the model group, two other groups, each with male and female sub-groups were used. The rats of the control group were fed regularly, and the rats of garlic groups were fed 1%, 3%, 5%, 7% of garlic mash, a high fat diet and water with 1% garlic juice. 30 days later, the level of hepatic triacylglycerol (TO) and total cholesterol (TC) in all groups were analyzed and compared. Results: (1) Compared with control group, the levels of TO and TC of liver in the model group were significantly increased (p < 0.01). There were significant differences between male and female rats in the levels of TO and TC (p < 0.05), and females were more susceptible to the high fat diet. (2) Compared with the model group, levels of TO and TC in garlic groups were decreased, and there was significant correlation between dose of garlic mash and the reduction of TC (male: R-2=0.9741, female: R-2=0.9655). Conclusion: The garlic diet had an effect on blocking the increases of TO and TC of liver in fatty liver-model rats, and the effect was different for male and female rats. Additionally, female rats were more sensitive to a high fat diet and a garlic diet.