Total sialic acid (TSA), C-reactive protein (CRP); alpha 1 acid glycoprotein (alpha 1-AG), and beta 2-microglobulin were determined in 84 patients affected by non-malignant intestinal diseases, Crohn's disease (CD) and ulcerative colitis (UC), active and in remission; non-ulcerative proctosigmoiditis; diverticulosis; diverticulitis (ie, inflammatory complication of diverticulosis). Only in patients with acute phase CD, TSA was statistically higher than those in remission, as well as in controls. In patients with acute CD and in those with diverticulitis, CRP was significantly higher than in the controls. alpha 1-AG was found significantly increased in acute UC and CD patients versus the respective groups in remission, as well as versus controls. Moreover, alpha 1-AG was higher in patients with diverticulitis. beta 2-microglobulin did not differ in any group of patients. In five patients with CD in acute phase, investigated before and during the pharmacological treatment (5-aminosalycilic acid and steroids), CRP values fell into the normal range after the second week of therapy, whereas TSA values reached the higher limit of the normal range after the third week, except for two CD patients with a larger location (ileocolonic) of the disease. The results are briefly discussed.