The specific classification of pain states can help guide therapeutic approaches, and often clinical pain states are complex and involve multiple mechanisms. The choice of drug treatment for acute pain is typically a function of the severity of the pain. The treatment of inflammatory pain typically focuses on reducing the inflammation. Unlike inflammatory pain, the current approved treatments for neuropathic pain focus on treating the symptoms and not necessarily the underlying causes. To better understand the role of translational medicine in the development of pain treatments, it is useful to have a general understanding of the drug discovery process for pain drugs with particular emphasis on the use of animal models that currently play a major role in identifying candidate molecules for clinical trials. In pain research the most commonly used neuroimaging techniques are functional magnetic resonance imaging (fMRI) and positron emission tomography (PET).