The investigations included a group of 26 patients with acute generalized tetanus, cared for in the Clinic according to a unitary method. A number of 17 prognostic, clinical and laboratory criteria were analyzed from the viewpoint of the pathogenic and clinicoevolutive incidence and significance. According to the severity, lethal course of the disease the following sequence was established in order of gravity: serum sickness, kypokaliemia, hyperpyruvicemia greater than an incubation of less 6 days, invasion within less than 24 hours, hyperlactacidemia greater than age over 60 years, persistent hypertension and tachycardia, hyperazoltemia, hyperglycemia, frequent paroxysmal contractions (before sedation) greater than late admission to hospital, associated cardiopulmonary pathology, hyponatriemia insufficient dressing of the wound and rural environment. The importance of the biological indices is emphasized, both as elements of prognosis and as orientative criteria for the treatment of the case.