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.
Patients with scanty, watery, and irregular catamenia sometimes suffer, about the time of the periods, from sick headache, and when this is the case a continued course of phosphorus increases the quantity and improves the quality and regularity of the menses, and the headaches frequently disappear. Phosphorus, like aconite, restores the discharge when suddenly interrupted by cold or fright.
When the discharge is not only too profuse, but watery in character, and rather delayed beyond the natural time, phosphorus is of considerable use, as it checks the overflow, relieves the backache, improves the mental depression, removes the nausea and vomiting so frequently attendant, and strengthens the general condition. It is also useful in profuse menstruation attended with excessive sexual excitement. The dose should rarely exceed 1/100 gr. every two to four hours during the menses, and morning and night during the menopause.