Creatine phosphate (CP), the phosphorylated form of the amino acid creatine, plays an important role in regenerating adenosine triphosphate (ATP) in skeletal muscle. Oral supplementation can increase muscle stores of creatine and seems to have significant ergogenic benefit for short-term activities requiring strength and power. Recently, supplementation has been implicated in having medical benefits as well. It may prove useful for restoring contractility in acute heart failure, prevention of ischemic injury during heart surgery, keeping energy levels from dropping in patients with systemic infection by acting as an ATP buffer, and treating patients with Duchenne's muscular dystrophy. However, despite the potential benefit of creatine supplementation, the safety issues have not been sufficiently examined. There does not seem to be any deleterious effects associated with short-term creatine use except for reported cramping, muscle tears, dehydration, and nausea. One potential-long term risk may be down-regulation of the expression of the creatine transporter protein. The safety of creatine supplementation needs to be further examined in order to deter misuse and abuse.