Sickness of animals with molybdenosis, caused by an excess molybdenum content in pasture plants, is encountered in England, Canada, USA, New Zealand and other countries. This sickness is characterized by diarrhea, loss of weight and change in color and falling out of the fleece. After it became known that molybdenum is a part of the enzyme xanthine oxidase, it could be assumed that the purine metabolism in an animal organism is disrupted in biogeochemical provinces enriched in molybdenum. With increase in molybdenum content of animal tissues, xanthine oxidase synthesis increases, which results in increased formation of uric acid in the organism and, under certain conditions, it can cause a gout type of sickness. The studies conducted enabled the question to be raised of the effect of the increased molybdenum concentration in the environment on human purine metabolism.