Four cases operated by the Scoville technique (orbital undercutting) are reported namely: two patients with mental deficiency and sexual exaltation, one with chronic schizophrenia and sexual exaltation and great agressivity, a boy sixteen years old presenting severe behaviour disturbances, specially on the sexual sphere, with agressivity. The theoretical basis for such an operation are based on Kleist's and Aníbal Silveira's ideas upon the psychophysiology of the orbital lobe. The end-results of the operation were satisfactory; there was a partial normalization of behaviour in the four patients. Unexpectadly the effect upon the sexual behaviour showed an evident correlation following the intervention on the left side, while the orbital undercutting on the right side has an effect specially concerning the agressive behaviour.