Rasburicase (Fasturtec) is an enzyme that transforms uric acid to the more water soluble allantoin to be excreted by the kidneys. Rasburicase fulfills an unmet clinical need in the treatment of hyperuricemia in that it produces a more rapid action of controlling serum uric acid compared with allopurinol. Tumours with high proliferative rate and sensitive to chemotherapy such as hematological malignancies (mainly) solid tumours (occasionally) may lead to a tumor lysis syndrome. In this situation rasburicase can effectively lower serum uric acid concentrations with a secondary improvement in renal function. Hyperuricemia is the hallmark of severe gout with tophi formation. Rasburicase represents an interesting new option in controlling serum uric acid in patients with severe tophaceous gout.