The purpose of this study was to evaluate the protective effects of Korean garlic juice against the toxicity of methyl mercuric chloride(MMC) about the fetal ossification in pregnant Fischer 344 rats, based on the theory and information that neutral amino acids in garlic juice have protective effects against mercury poisoning. We orally treated the 20 mg MMC/kg body wt. and 0.5 and 1.0 garlic juice/kg body wt. on the 7th day of gestation, and extract fetus from the dams on 20th day of gestation. And the fetal bones were stained and measured. The results obtained are as follows : 1. Fetal body weights, body lengths, and head length were significantly decreased as much as 23.5%, 21.3%, 15.5% in 20mg/ wt kg methyl mercuric chloride groups (p<0.05). But in garlic treated groups, they were almost similar with controls. 2. The ossification centers were significantly decreased as much as 35.1% in pelvic phalanges, 53.5% in pectoral phalanges, 74.1% in ternebrae, 76.2% in tail of 20 mg/wt kg methyl mercuric chloride groups (p<0.05). But in garlic treated groups, they were significantly increased as much as 81.2~88.7% and 94.8~98.9% of controls. 3. The ossified pectoral girdles were significantly decreased as much as 66.6% in clavicle, 74.2~87.4% in the others of 20mg/wt kg methyl mercuric chloride groups (p<0.05). But in garlic treated groups, they were significantly increased as much as 81.2~88.7% and 94.8~98.9% of controls. 4. The ossified pelvic girdles were significantly decreased as much as 57.1% and 56.1% in 2 ischium, 67.2~81.7% in metacarpals of 20 mg/wt kg methyl mercuric chloride groups (p<0.05). But in garlic treated groups, they were significantly increased as much as 67.0~85.6% and 90.1~98.7% of controls. 5. The ossified terenebrae were significantly decreased as much as 0.0% in 5th, 54.1% in 2th, 83.9% in 2nd, 75.0% in 3rd, 72.7% in 4th, 79.8% in 6th of 20 mg/wt kg methyl mercuric chloride groups (p<0.05). But in garlic treated groups, they were significantly increased as much as 29.5~55.1% and 54.5~84.0% of controls. 6. The ossified ribs were significantly decreased as much as 8.3~18.0% in 20 mg/wt kg methyl mercuric chloride groups (p<0.05). But in garlic treated groups, they were significantly increased as much as 87.1~93.5% and 96.3~99.7% of controls. In conclusion, Korean garlic juice significantly protected against the toxicity of MMC about the fetal ossification in pregnant rats.