Arndt-Schulz rule
Encyclopedia
Arndt–Schulz rule or Schulz' law is a claimed law concerning the effects of pharmaca or poisons in various concentrations. It states that:
That is to say, highly diluted pharmaca or poisons enhance life processes, while strong concentrations may inhibit these processes and even terminate them.
The rule was named after Hugo Paul Friedrich Schulz
and Rudolf Arndt
. The latter originally formulated it in 1888. However, the exceptions to the rule are so numerous that it can not be considered a general law. For instance, many paralysing substances have no exciting effect in weak doses, and what constitutes a weak, medium or strong stimulus is highly individual, as pointed out by Arndt himself.
The rule is no longer cited in modern pharmacology
texts, having been supplanted by the theory of hormesis
.
This rule has been claimed by homeopaths as supporting their theories. However, it gives no support to the dilutions typically used by homeopaths which have a high probability of containing no molecules of the diluted substance. This objection led to the postulation of "water memory
", but subsequent research has shown that such an effect cannot persist for as long as a nanosecond.
- For every substance, small doses stimulate, moderate doses inhibit, large doses kill.
That is to say, highly diluted pharmaca or poisons enhance life processes, while strong concentrations may inhibit these processes and even terminate them.
The rule was named after Hugo Paul Friedrich Schulz
Hugo Paul Friedrich Schulz
Hugo Paul Friedrich Schulz was a German pharmacologist from Wesel, Rhenish Prussia. He studied medicine in the universities of Heidelberg and Bonn, where he did scientific work in the physiological institute of Eduard Friedrich Wilhelm Pflüger...
and Rudolf Arndt
Rudolf Arndt
Rudolf Arndt was a German psychiatrist from Bialken, district of Marienwerder.Arndt studied in Greifswald and Halle, preferably under Felix von Niemeyer , Heinrich Adolf von Bardeleben , and Heinrich Philipp August Damerow , and was conferred doctor of medicine on 20 February 1860...
. The latter originally formulated it in 1888. However, the exceptions to the rule are so numerous that it can not be considered a general law. For instance, many paralysing substances have no exciting effect in weak doses, and what constitutes a weak, medium or strong stimulus is highly individual, as pointed out by Arndt himself.
The rule is no longer cited in modern pharmacology
Pharmacology
Pharmacology is the branch of medicine and biology concerned with the study of drug action. More specifically, it is the study of the interactions that occur between a living organism and chemicals that affect normal or abnormal biochemical function...
texts, having been supplanted by the theory of hormesis
Hormesis
Hormesis is the term for generally favorable biological responses to low exposures to toxins and other stressors. A pollutant or toxin showing hormesis thus has the opposite effect in small doses as in large doses...
.
This rule has been claimed by homeopaths as supporting their theories. However, it gives no support to the dilutions typically used by homeopaths which have a high probability of containing no molecules of the diluted substance. This objection led to the postulation of "water memory
Water memory
Water memory is the claimed ability of water to retain a "memory" of substances previously dissolved in it to arbitrary dilution. No scientific evidence supports this claim. Shaking the water at each stage of a serial dilution is claimed to be necessary for an effect to occur...
", but subsequent research has shown that such an effect cannot persist for as long as a nanosecond.