Lead (Pb) intoxication in horses is usually a chronic phenomenon with clinical signs associated with central nervous dysfunction. This report gives details of a case of acute Pb intoxication in a 9-year-old American Saddlebred mare with severe, progressive and ultimately fatal neurological deterioration. During the 4 days of hospitalisation, clinical signs progressed from intermittent headshaking and depression to severe, continuous, uncontrollable manic behaviour. At autopsy, three grey-coloured, hard metal particles were present in the gastrointestinal tract and subsequently found to contain 2614 ppm Pb. Lead concentrations in the brain, liver, stomach and kidney were 29, 4, 6 and 2 ppm wet weight, respectively.