Seven patients, six suffering from amyotrophic lateral sclerosis (ALS) and one from Friedreich ataxia, were treated with a placebo i.v. infusion during the first day and with TRH-T i.v. infusion at a rate of 2 mg/h for 8 h daily (total daily dosage 16 mg) on the 2 consecutive days. Continuous blood pressure (BP) and EKG monitorings were performed during 3 days infusion. Blood samples were collected for endocrinological evaluations. The neurological evaluation after acute TRH-T treatment showed an objective improvement in 3 of the 8. We found significantly higher values of systolic (max. difference of 10.1 mm Hg) and diastolic (max. difference of 8.8 mm Hg) BP than during placebo, beginning from the 5th h of the infusion (p less than 0.05). A trend in progressive increase of the heart rate (HR) reached statistical significance (p less than 0.01) at the 8th h of the second TRH-T infusion. The cardiovascular changes during the i.v. continuous TRH-T infusions were clinically irrelevant and never required the interruption of the treatment.