The key to homeopathic potency selection boils down to finding the susceptibility of our patient. What factors determine the susceptibility? Susceptibility depends on the following factors:
Nature of the Constitution – Age; children or older, Physical Constitution and Psychological temperament. Is the patient sensitive, quick to act and react? or are they sluggish, dull, and slow to act? Habits and environment also play a part: What is their occupation? Do they lead a sedentary life? Is there exposure to chemicals?
Idiosyncratic patients usually have an excessively high susceptibility.
Nature of Disease – Seat of disease, Nature of disease, Stage of disease. Is it a dynamic vs fixed disease? Is it a disorder that involves rapid development, hyperactive tendencies, allergenic responses, and nervous irritability? Is the disease of an insidious nature?
Nature of the Remedy – remedy reactivity, duration and depth of action. What kingdom does the remedy come from? i.e. plant, animal, mineral? and Is the medicine Potent vs inert remedies in crude forms?
When in a case, the symptoms of a patient are very well matched by the symptom picture of the drug, and especially if the mental symptoms are present and clearly marked, then a high potency seems advisable.
Where the symptom matching is poor due to paucity of symptoms or when the prescription covers only a superficial or local condition eg. a skin condition such as a wart, or where pathological symptoms predominate eg. as in cancer, congestive cardiac failure, or where only a palliation is aimed at because the patient is incurable and has a very low vitality, low potencies seem more advisable.
Children appear to tolerate high potencies well due to their vitality, while old persons may not tolerate high potencies so well.
As always, it is advisable to seek advise from your experienced professional before administering any homeopathic remedies, in any potencies.