A 13-year-old intact male poodle had suffered periodic tetanic crises for two months. It was cachectic and moderately dehydrated, and during the crises blindness, a stiff gait and behavioural changes were observed. Routine haematological and biochemical profiles showed that it was severely hypocalcaemic, with a corrected plasma calcium concentration of 1˙13 mmol/litre (reference range 2˙25 to 3 mmol/litre). The dog was fed a home-made diet composed of chicken and basmati rice cooked with a soup bouillon cube; an analysis of its daily allowance indicated that the dog was generally malnourished and received only 0˙222 g of calcium per day rather than the 0˙6 g it required. In addition, the dog had a low blood concentration of parathyroid hormone of 12 ng/litre (reference range 20 to 80 ng/litre). Supplementing the dog with calcitriol for four days and correcting its diet increased its blood calcium to the lower part of the reference range and resolved the clinical signs, although its parathyroid hormone concentration was still low one year later.