A method for treating hypoparathyroidism and/or hypocalcemia by local administration of a neurotoxin, such as a botulinum toxin, to a parathyroid gland, thereby reducing an inhibitory effect upon parathyroid hormone secretion. A method for treating hyperparathyroidism and/or hypercalcemia by local administration of a neurotoxin, such as a botulinum toxin, to a sympathetic ganglion which innervates a parathyroid hormone secreting parathyroid cell, thereby reducing a stimulatory effect upon parathyroid hormone secretion.