Pithed frogs have undergone the pithing procedure, which involves a needle inserted through the foramen magnum into the cranial cavity. Pithing mechanically causes disruptions within the frog's brain, and it is an approved euthanasia method for amphibians.
Pithing a frog is performed in scientific experiments concerning frog reflexes, and a second step, "double pithing," involves destroying the spinal cord, again testing behavior reflexes. The scientific reasoning behind pithing a frog is to determine which behaviors require the spinal cord and brain working together, which behaviors require the spinal cord only or brain only, and which behaviors require neither. Frogs should be cleaned prior to pithing.