The effect of two dehydrated apple products (10% in diet)--apple pulp (crude fibre 3.5%, pectin 1.4%) and apple pomaces (crude fibre 13.5%, pectin 7%)--on the serum and liver lipids of growing Syrian male hamsters were studied. The animals were fed a natural diet (38% of energy substituted by milk fat; the diet contains 53 mg of cholesterol (CH) per 100 g) which resulted in an accumulation of CH and triacylglycerols (TG) in the serum as well as in the liver, and CH-rich very low density lipoproteins (VLDL) in the circulation. After two months both apple products decreased the levels of CH and TG in serum (by 40-70%) and the content of CH in VLDL with similar efficiency. Both products reduced CH content in the liver, and the apple pulp also decreased TG content. Up to the 6th month the apple pulp studied suppresses accumulation of CH and TG in both the serum and the liver. A complete analysis of lipoproteins of main density class at the time showed that the decrease of serum CH and TG to a decisive extent is due to the decrease of their concentration in VLDL (by more than 50%). Therefore, the concentration of VLDL and the whole lipoprotein pool decreased by 50%. The apple pulp doubled the amount of CH transported by HDL. Three months after the replacement of butter in the diet by corn germ oil the CH and TG levels in the serum and TG also in the liver decreased to the physiological level.(ABSTRACT TRUNCATED AT 250 WORDS)