60 consecutive patients (age 15-77 years) with the Guillain-Barré syndrome were studied. 37 subjects had an antecedent infection. Onset occurred with motor and/or sensory limb symptoms in 56 cases; 4 subjects experienced onsets with pain, diplopia or bladder disturbances. The motor symptoms reached a maximum within 42 days in all cases, 87% within less than 20 days. All patients had limb-muscle weakness at the symptomatic maximum: 50% exhibited cranial-nerve affections and 10 subjects has respiratory insufficiency. Signs of a remission appeared within 60 days after onset in all cases surviving the maximal phase, 81% within less than 40 days. The CSF protein concentration was elevated (0.6-7.8 g/l) in 95% of the patients; an increased mononuclear cells count 6-60 X 10(6)/l) occurred in 27% of cases. Electrophysiological abnormalities were detected in 42 out of 43 examined cases. Totally there were 4 deaths, all caused by cardiac or thrombo-embolic events. Surviving patients had restitutions without functionally significant sequelae within less than 6 months after onset in 73% of cases; all but 2 of the remaining patients recovered within 18 months. The degree of muscle weakness at maximum was the predominant prognostic factor.