We report one case of amicrobic pustulosis cured with Dedrogyl (25-hydroxycholecalciferol), active metabolite of the vitamin D. The importance of our case stems from the physiopathologic study of this cure. The patient is a 16-year-old boy suffering from a hypoparathyroidism since his younger days. Consequently, he shows a hypocalcemia and convulsive seizures due to the hypoparathyroidism. Those seizures had been wrongly attributed to a primary epilepsy of a neurologic origin and a treatment with Phenobarbital had been instituted. In fact, they were side-effects of the hypoparathyroidism and the Phenobarbital had only aggravated the hypoparathyroidal hypocalcemia as a result of its effect on the metabolism of the vitamin D (deviation of this metabolism by enzyme induction at the level of the liver). The Dedrogyl (25-hydroxycholecalciferol) has restored a normal phospho-calcium balance and the hypocalcemia has disappeared as well as the convulsive seizures which, one year later, had not reappeared while they had previously been continual. And above all, standing back one year, we have recorded a complete cure of the amicrobic pustulosis on account of the Dedrogyl.