Blood serotonin level, 5-HIAA in 24 h urine, serum immunoglobulins-IgG, IgM, IgA, percentage of lymphocytes T and B in rosette test were ascertained in 3 groups of patients with taeniosis, treated with Radeverm (32 patients), Praziquantel (22 patients) and Yomesan (10 patients). Primary