Mercury poisoning was diagnosed in four dairy heifers, three of which died. The clinical signs were variable and included salivation, excessive thirst, extreme depression and severe diarrhoea. Postmortem examinations revealed inflammation and ulceration of the alimentary tract, pulmonary and cardiac haemorrhages, pallor of the kidney cortices and perirenal oedema. The kidney mercury concentrations were in the range 58 to 91 μg/g wet tissue. It is believed that the animals were poisoned by the ingestion of soil contaminated with mercurous chloride.