In 24-h water- and food-deprived rats, we have evaluated the effects of cromoglycate sodium salt, an inhibitor of the mast cell degranulation with anti-inflammatory and membrane-stabilizating activity, on the central effects induced by Escherichia coli lipopolysaccharide (LPS). Intraperitoneal (i.p.) injection of LPS (0.25, 0.50 and 1 mg/kg) induced a dose-dependent inhibition of water and food intake, fever, reduction in locomotor activity as well as increased anxiety levels. All these LPS effects were antagonized by a prior intracerebroventricular (i.c.v.) injection of cromoglycate sodium salt (100, 150 and 200 microg/rat). Our findings suggest that peripheral LPS administration may activate brain mast cells and indicate an involvement of these cells in brain pathophysiology.