The popularity of this drug among some athletes is due to the anabolic effect together with the fat reducing effect of this drug, even though there is, to my knowledge, no clinical evidence that can support such effects. The likely explanation is that the fat is re-distributed into the muscle. In many countries clenbuterol is only prescribed to animals and is used e.g. for respiratory disease in horses and in cattle to relax the uterus at the time of parturition. It is also used illegally in pigs to obtain leaner meats. There have been several reported occasions where people have been poisoned by eating pork contaminated by clenbuterol.