Phenylbutazone, often referred to as "bute", is a nonsteroidal anti-inflammatory drug (NSAID) for the short-term treatment of pain and fever in animals. In the United States and United Kingdom it is no longer approved for human use (except in the United Kingdom for ankylosing spondylitis), as it can cause severe adverse effects such as suppression of white blood cell production and aplastic anemia. [Source: Wikipedia ]