Homeopathy in a nutshell: Posology and Dosology
Dosology refers to the quantity of a remedy that is given and posology to the actual frequency of administration of this dose . In Aphorism 2 of the Organon Hahnemann specified that the highest ideal is to restore a patient to health rapidly, gently and durably. To do this, a careful selection of the appropriate remedy is a prerequisite, followed by the administration of the adjusted dose as not to overstress the vital force, and a cautious selection of remedy repetition .
In terms of dosage of a remedy, this must be large enough to overcome the opposition of the vital force and be sufficient to induce a curative action  and is dependant, as is the potency of a remedy, on factors such as sensitiveness of the patient, nature of the disease and remedy prescribed . Bhatia  in his Guidelines to the 6th Organon points out that in an acute case a single dose may be sufficient to resolve the case, but in a chronic case a repeated split dose may be more effective (Aphorism 246). The dosage should be altered with each administration of the prescribed remedy; which is best done by increasing the number of succussions and does not necessarily request an alteration of potency (Aphorism 280).
The prescription should only be repeated if the patient shows little and slow improvement. Should the patient experience evident and obvious amelioration, a repeated intake of the remedy could aggravate and slow down the healing process  and should thus be avoided. A repetition of dose becomes necessary if the symptom picture returns or has not fully improved. If a new picture arises a layer has been removed and a second latent miasmatic condition is revealed, in this case a different picture has presented that will require a new and altered prescription . Hahnemann  points out in aphorism 276 of the Organon that great disaster is caused if dosage is too great or repetition is too extensive; not seldom is the patient rendered in danger of life or his ailment is rendered incurable.
Therefore, following remedy administration, interference by dose repetition should be avoided, until signs of improvement relapse . A single dose is appropriate unless a strong initial aggravation is expected and a split dose is required for minimization of such ;. The split dose is administered in a first dose that is effective in delivering the remedy information and a second dose that cuts off the full expression of the remedy in the patient; thus preventing a possible aggravation from occurring . Roy  points out, that it is important to control the aggravation of a repetitive dose in that the healing movement is to be enhanced and not the disease.
In aphorism 275 Hahnemann  stated that the adequacy of a prescription is not only dependant on the matching remedy but equally as much on the requirement of the appropriate dosage and the minuteness of the posology.
[Many thanks to Ian Townsend, University of Central Lancashire, U.K., for his assistance with this assignment]
1. Bhatia (Anon) Guidelines in 6th Edition of Organon of Medicine (1842) [online] last accessed 06.04.09 at URL http://www.hpathy.com/software/posology/help/Organon6.htm
2. Close, S. (2000) The Genius of Homeopathy Lectures and Essays on Homeopathic Philosophy Chapter 13 [online] last accessed 07.04.09 at URL http://homeoint.org/books4/close/chapter13.htm
3. De Vries, A. (2004) Homeopathic dose [online] last accessed 06.04.09 at URL http://www.hompath.net/homeopathy/homeopathic-dose.php
4. Hahnemann, S. (1974) Organon der Heilkunst (2.Auflage) 6B Heidelberg:Karl F. Haug Verlag.
5. Little, D. (2006) Hahnemann´s advanced methods [online] Homeopathic ezine, last accessed 06.04.09 at URL http://www.hpathy.com/philosophy/little-medicinal-solution.asp
6. Little, D. (2007) Dose and Potency according to the Organon [online] last accessed 06.04.09 at URL http://www.simillimum.com/education/little-library/case-management/dpato/article.php
7. Roy, M. (2006) Homeopathic case analysis Kilmarnock, Ritchie UK Ltd.