The red blood cell metabolic parameters ATP, ADP, sigma AN, ATP/ADP, ATP/ATP, energy charge, PAD, 2,3-DPH, Pn were studied in 106 patients with generalized meningococcus infection (GMI) and meningitis of other etiology over their natural history. There was a typical adaptative red blood cell response that featured glycolytic stimulation on hypoxia that ran with impaired red blood cell energy metabolism (RBCEM), negative energy balance. It was the most pronounced at the peak of disease. RBCEM changes occurred in the presence of antioxidative disorders of red blood cells as lowered PAD levels. When early complications, such as shock, brain edema, death developed, there was a high incidence of signs of erythrocytic biochemical disadaptation. The RBCEM changes were associated with the magnitude of cytolysis, i.e. serum AST and AST/ALT levels. The significance of the metabolic changes found in the red blood cells in the pathogenesis and clinical picture of GMI and purulent meningitis is discussed in the paper.