Question: Am I wrong in believing iron overload in horses can be caused by high iron in water? The only consistent thing in my horse's diet over the last 20+ years has been the water. I don't give feed or supplements on a consistent, daily basis and very rarely do I stay consistent with where my hay comes from. I've had several vets, including my current one tell me it's not possible to get it from the water. But over the years the health symptoms have told me otherwise. I'm so frustrated trying to figure this out. Thank you. Dr. Kellon: It most certainly is possible. Below is a presentation from the EU. HEMOCHROMATOSIS AND LIVER FAILURE IN 11 HORSES DUE TO CHRONIC IRON INTOXICATION  Theelen MJP1, Beukers M2, Grinwis GCM3, Sloet van Oldruitenborgh-Oosterbaan MM1 Iron toxicosis is rarely reported in horses and chronic excessive oral iron intake is thought not to cause any clinical symptoms in horses. This case series describes 11 genetically unrelated horses with evidence of liver damage due to chronic intake of excessive amounts of iron. The first case presented with hepatic encephalopathy. At necropsy excessive iron accumulation was found in several organs including the liver (hemochromatosis). Further examination of all horses on the same farm showed poor body condition scores and rough hair coats. Serum iron was increased in ten horses (mean of all horses 73,3±15,6 μmol/l; normal 18-54 μmol/l) and iron saturation levels were increased in all horses (mean 90.7±2.6%; normal 40%). Ten horses had elevated GGT (mean of all horses 910±635 IU/l; normal <34 IU/l) and nine horses had increased bile acids (mean of all horses 29±23 μmol/l; normal <11,5 μmol/l). Other elevated parameters in affected horses were total iron binding capacity, AF, AST, LDH, ammonia, WBC, TP and beta-2-globulins. Ultrasonographic evaluation of the liver of five horses showed in all five enlargement of the liver with increased echogenicity and histologic evaluation of liver biopsies showed severe hemochromatosis and cirrhosis. Water, soil and feedstuff were analysed for iron content: water iron level 72,5 mg/l (acceptable <0.5 mg/l), iron levels in soil and feedstuff were not increased. It was concluded that the drinking water (ditch) was the source of the excessive iron intake and this study indicates that chronic excessive iron intake can lead to hemochromatosis and liver failure. 1 Utrecht University, Faculty of Veterinary Medicine, Department of Equine Sciences – Internal Medicine, Yalelaan 114, 3584 CM, Utrecht, The Netherlands 2 Utrecht University, Faculty of Veterinary Medicine, Department of Clinical Sciences of Companion Animals – Diagnostic Imaging, Yalelaan 108, 3584 CM, Utrecht, The Netherlands 3 Utrecht University, Faculty of Veterinary Medicine, Department of Pathobiology – Veterinary Pathology Diagnostic Centre, Yalelaan 1, 3584 CL, Utrecht, The Netherlands