Marking Homeopathic X and C Potencies

During many years of my practice, I have felt that some of us are not clear or aware of the meanings of letter "X" or "C" written with the number to indicate a potency. Most of the times (specially in email consultations) when I prescribe a 200 potency for example, and miss out writing "C" with it, I receive a question whether it is 200X or 200C. If I write 1M, I get a query that 1M is not available, M potency is available instead. This made me to think that there is a need to clarify the concept and the difference between X and C potencies and other letters used with the numbers for marking. This short article has been written with the hope that it will be of some help in understanding how homeopathic potencies are made and marked.

Mother Tincture and Trituration

Homeopathic medicines are prepared from different source materials, some of which are soluble in water or alcohol but some are not. Mother tinctures are prepared from those substances which are soluble whereas "triturations" are prepared from those which are not soluble. Mother tinctures are liquids but triturations are dry preparations. These mother tinctures (always denoted by ‘Q’) and triturations are the basic potencies which are used to prepare further (higher) potencies.

The substance like alcohol, water or powder (sugar of milk) used to prepare the medicine is called "vehicle" in homeopathic terminology.

There are several systems to raise the potency but in general practice, two systems are being used; namely, the "Decimal System" and the "Centesimal System".

Decimal System

In this system, one part of the medicinal substance and nine parts of the vehicle are used (ratio of 1:9, 1+9=10). It is due to this ratio that the system is called "Decimal System" and is denoted by letter "X" which stands for number 10 in Latin. The vehicle may be water, alcohol or anything else, dry or wet. Basically, any medicine whether biochemic or homeopathic, powder or liquid, if prepared under decimal system will have letter X written with the number of the potency like, 3X, 6X, 12X, 30X, 200X etc. It is always written after the number. This convention is followed by almost all the countries.

The only purpose of this letter X is to indicate that it has been prepared under decimal system and not to differentiate between powder or liquid, homeopathic or biochemic etc. Letter X does not indicate the source of the medicine either.

Centesimal System

In this system, one part of the medicinal substance and ninety nine parts of the vehicle are used (ratio of 1:99, 1+99=100). Like decimal system, it is due to this ratio that the system is called "Centesimal System" and is indicated by letter "C" which is used for number 100 in Latin.

Medicines which are prepared under "Centesimal System" should as a matter of principle, have letter C written with the number of the potency to indicate that it has been prepared under Centesimal system, like 30C, 200C etc. Like letter X in the decimal system, letter C in centesimal system is also always written after the potency number. If letter C is found before the number, it is to be taken as 100 while reading the number. For example, a CM potency would mean 100M or hundred thousand.

Having understood this, if we now compare 30X and 30C potencies, it will be seen that the ratio between the medicinal substance and the vehicle in both the potencies will not be the same. Therefore, 30X potency cannot be the same as 30C. Similarly a potency marked as 200X cannot be the same as 200C. The purpose of using letters "X" or "C" is to indicate the system under which they have been prepared and not to indicate the effectiveness.

What if no letter is found with the number of potency

Unlike decimal system, writing letter C as indication of centesimal system is not considered necessary in all the countries. In many countries (including Pakistan) it is conventionally understood that if any of the letters X or C is not written after the number, it would be understood as a preparation under centesimal system. Thus a potency indicated as 30 or 200 would mean that it has been prepared under centesimal system and is the same as 30C or 200C prepared in another country which prefers to write letter C after the number. Similarly, any homeopathic medicine with potency indicated as 1000 or 1000C would mean the same thing.

Same is the case with higher potencies. Please note letter "M" stands for number 1000 in Latin. Thus M potency would mean the same as 1M (which is actually 1×1000). Now if we put it all together, potency number 1000, 1000C, M or 1M indicate the same thing. Similarly, 30 and 30C would mean the same potency. So is the case with 200 and 200C.

Any medicine which has been prepared under some other system should accordingly have an indicator on the container.