Experiments were performed on 9 sheep divided into three groups: I – control; II – treated i.m. with hydrocortisone (20 mg/kg b wt) for 5 days; III – treated with C plus vit.C (20 mg/kg b wt i.m.). for 5 days. Administration of hydrocortisone decreased bile flow to 6.65 ±1.35 μl/min/kg b wt in 165 min. Addition of vit. C resulted in increase (p<0.05) of bile output to mean value 12.059 ±0.937 μl/min/kg b wt. Under stressful conditions increase (p<0.05) of biliary concentration and secretion of malondialdehyde (MDA) was observed (max. 0.952 ±0.123 μM/min/kg b wt in 120 min.). Thus, biliary level of this compound seems to be a useful marker of oxidative stress in liver. Exposition to vit. C caused reduction of biliary output of MDA averaged at 0.461 ±0.029 μM/min/kg b wt. Biliary cholesterol (CH) concentration in hydrocortisone-treatment sheep gradually increase to max. 191.75 ±8.31mg/100ml in 105 min. After vit. C administration considerable (p<0.05) reduction of biliary level of this compound was observed. On the other hand, elevation of biliary output of CH to highest value 18.965 μM/min/kg b wt in 135 min of experiment was found. In conclusion, administration of ascorbic acids ameliorates glicocorticoids induced lipid peroxydation and cholesterol crystal formation in liver.