Abstract: The present invention relates to a method of diagnosing and treating neuropathic pain syndromes with a composition of which Pelaroonium graveolens Ait. oil is the principle therapeutic agent. This oil is alternatively called geranium oil bourbon, oil geranium reunion, and oil rose-geranium. In particular, this invention discloses a method and composition to be used in treating and diagnosing neuropathic pain syndromes, including but not limited to Postherpetic Neuralgia and Reflex Syndrome Dystrophy, in which geranium oil bourbon is applied topically to the area affected with neuropathic pain symptoms.This invention provides a previously unavailable method for distinguishing pain caused by Postherpetic Neuralgia or by Reflex Syndrome Dystrophy from that caused by a host of other neuropathies. Additionally, this invention provides a previously unavailable means of treating the often unbearable pain caused by these two neuropathies.