This section is from the book "Materia Medica And Therapeutics Inorganic Substances", by Charles D. F. Phillips. Also available from Amazon: Materia medica and therapeutics.
Before the introduction of many modern remedies for neuralgia, large doses of the carbonate or oxide of iron were much relied upon, and when there is a chlorotic anaemic condition of system they are of service. I should not myself consider iron a remedy for "idiopathic neuralgia," but some observers have attributed to it almost a specific power, especially in neuralgiae of the fifth nerve: thus, Mr. Hutchinson recommends it in "prosopalgia," and, according to Schobelt, the phosphate of iron acts well in neuralgia of the teeth: the citrate of iron and quinine is a very good form when the remedy has to be long continued.
When neuralgia of the stomach occurs in anaemic or chlorotic patients, who complain of cramping pain and distension, accompanied with nausea and vomiting of mucus and water, principally before breakfast, and of frequent acid and insipid eructations after meals - iron is useful, especially when the neuralgia depends on loss of blood or on protracted diarrhoea; I have notes of many such cases cured by it.