68 patients have been treated by regional intravenous blocks with guanethidine. 251 blocks have been realized. The majority of the patients received 3 blocks of one week. Some of them got a second series of 3 blocks after a minimum interval of one month. The study included 3 groups of patients. The first group showed 12 patients in the first stage of Sudeck; the second group 22 patients in the second stage. The third group included 34 patients for which the indication to blockade had been a chronic painful stage (19 cases), an ankylosis (8 cases), a Dupuytren post-traumatic contracture (3 cases) a stage before the operation predisposing to dystrophy reflex (3 cases) and one case of hyperhidrosis of the hand. Considering the three groups it can be stated that the first one responded the best to the treatment with a success in 80% of the cases. This success confirms the necessity of intervening as soon as possible in case of an algoneurodystrophy. The third group reveals that this therapeutical method can be useful in other situations than the dystrophy reflexes. The indication herewith is more founded on a possible sympathetic origin of the troubles as on the comportment psycho-affective of the patient.