Hypercalcemia and ectopic calcification were induced in 5 lambs by supplementing the diet with the dried leaves of the plant Cestrum diurnum, for 8 to 9 weeks. Lambs developed mineralization of blood vessels, heart, kidneys, and lungs. These tissues were examined by light and electron microscopy. In the vascular tissue there was calcification of elastic fibers in the hyperplastic intima and the media, along with mineralization of mitochondria of aortic smooth muscle cells. Myocardial cells and their mitochondria were mineralized. In the kidney, there was calcification of the epithelium of the distal convoluted tubules and collecting tubules, Bowman's capsule, and the mesangial cells of the glomeruli. In the lung, there was mineralization of the alveolar septal walls and the bronchi and bronchioles. Feeding of the calcinogenic plant to lambs caused extensive soft tissue calcification. Results of the study indicated that degeneration was the early soft tissue lesion in this plant toxicity.