Use:

An injection of sodium pentobarbital is considered by many to be the most humane method of euthanasia. Acquiring, possessing, and using this drug is strictly regulated by state and federal laws. For this reason, you must seek the assistance of a veterinarian or a specially licensed dog pound or animal shelter when using this method to euthanize an animal. The carcasses of animals euthanized by drugs, except for the hide when it may be legally sold, must be disposed of by burial, incineration, or disposal in a landfill. These carcasses cannot be sold or given away.