The biological effects of bio-yoghurt fortified with glycomacropeptide (GMP) and crude virgin olive oil (CVOO) and Bifidobacterium bifidum Bb12 were investigated on rats. The rats were fed on basal diet and experimental diet in appropriate amounts of basal diet and yoghurt in the ratio 1:1 (W/W) and fresh water were supplied with meal for 21 days compared to control (-) which fed on basal diet only. Rats were arranged in 4 groups, 5 rats each. The results revealed no significant differences between rats' initial body weight whereas a significantly different (p˂0.05) between rats' final body weight and body weight gain and there is a relative difference in liver, spleen, kidney and heart weights between treated groups and control (-) group (IV), moreover histopathological examination of rats liver tissues indicated the healthful effect of feeding on yoghurt fortified with GMP,CVOO and B. bifidum compared to control ( - ), also all groups fed on yoghurt fortified with GMP,CVOO and B. bifidum showed ahipolipidemic action demonstrated by a significant reduction in the concentration of plasma cholesterol, triglycerides and phospholipids and tended to lower plasma low density lipoprotien (LDL) cholesterol concentration and leading to lowering liver enzymes; glutamic-pyruvic transaminase (GPT) and glutamic-oxaloacetic transaminase (GOT), moreover the rats fed on yoghurt fortified with food additives and B. bifidum had higher counts of lactic acid bacteria and B. bifidum, and lower counts of staphylococci and coliforms.