Digitonin is a plant steroid that belongs to steroids sapogenin, C 27 -steroid. Digitonin contains 1 mol of digitogenin, 2 mols of glucose and 1 mol of xylose. Saponins in complex with cholesterol and other 3 β-hydroxysterols form molecular compounds such as cholesterol digitonide. Digitonin and its analogues damage liposomal elements of plasma membranes and cause haemolysis of red cells. These compounds activate granulocytes as well (Nishikawa et al., 1984;Sancho et al., 1993). Clarke and Hillard (1981) were interested in the effect of digitonin on hepatic cells in broiler chickens. The authors found out that plasma cholesterol disappeared from plasma membranes and it caused perforation of plasma membranes as a result of elimination of plasma cholesterol. Digitonin inactivates acetyl CoA carboxylase by means of its transformation to inactivated form. This process reduces fa�y acid synthesis. Haeffaner and Wi�mann (1999) observed the effect of cholesterol -digitonide on the growth of ascites tumour cells. According to their description cholesterol -digitonide influenced phospholipase C activity. Phospholipase C activity could be increased synergistically in cholesterol -digitonide treated cells.Digitonin is known as a substance that influences mainly cholesterol metabolism. The use of this compound results in a lower plasma cholesterol concentration, the modulation of the regulatory mechanism of hepatic metabolism (Ulloa and Nervi, 1985). These authors reported that digitonin decreased liver weight, bile flow and biliary cholesterol secretion in rats. Eastwood and Hamilton (1968) suggested that sterols inhibited bile acid reabsorption, thereby decreasing cholesterol body stores. According to Clarenburg et al. (1971) egg cholesterol levels in hens were lowered by 35% when 4% sitosterol was added to a standard diet. However, Bartov et al. (1971) found no effect of soybean sterols on egg yolk cholesterol levels. Fisher and Griminger (1967) found slightly higher plasma cholesterol-lowering effects from soybean sterols. The aim of the present study was to describe the effect of digitonin on egg quality, cholesterol content in eggs, some parameters of serum lipid metabolism and blood picture of laying hens. The experiment was split into 3 groups (8 laying hens per group); group 1 was fed control feed mixture with 16.54% crude protein and 11.61 MJ ME, group 2 received control feed mixture with 0.01% digitonin and supplement of digitonin in group 3 was 0.025%. Digitonin in the amount 0.025% significantly (P ≤ 0.05) reduced egg weight from 65.07 g in control group to 61.44 g in group 3, white weight (41.21 g vs. 37.96 g), and egg cholesterol content (13.64 mg/g vs. 12.95 mg/g of yolk). Digitonin significantly (P ≤ 0.05) increased HDL cholesterol (0.43 mmol/l in control group to 0.59 mmol/l in group 3) and triglycerides from 13.47 mmol/l (control) to 16.90 mmol/l (group 3) in blood serum. Significantly (P ≤ 0.05) lower number of erythrocytes and MCV value in group 3 were observed.Keywords: digitonin; egg weight; lipid met...