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Toxicology and Applied Pharma

Letters to the Editor

Hormesis is not homeopathy

In his article, Calabrese (2005) gives hormesis a

strong association with homeopathy as a leading reason

for its marginalization by the medical establishment.

Without getting into a discussion on the validity of

homeopathy, we contend that this linkage is miscon-

ceived. Homeopathy and hormesis indeed share in

common the use of small doses, but differ conceptually

on at least four important issues:

(1) Unlike the non-specific effect of hormesis, induced by

a variety of chemically unrelated substances, homeo-

pathy is highly specific. A homeopathic remedy that

does not bfit like a gloveQ will not elicit biological

activity.

(2) Whereas hormetic (chemical) responses are induced

by small but measurable concentrations (above

Avogardo’s number), homeopathic concentrations

are often far below this. The use of a remedy with

a bconcentrationQ of 10�400 of the stem solution is

common practice in classic homeopathy.

(3) The hormetic effect is reversible, reverting with

cessation of the hormetic substance. The homeo-

pathic effect is enduring. A single exposure initiates a

healing process which continues long after adminis-

tration of the remedy.

(4) Hormetic substances do not require any special

preparation. Homeopathic remedies, in contrast,

require a lengthy and exacting process before they

are ready for administration.

It appears to us that the medical establishment’s neglect

of hormesis stems more from hormesis’s lack of clear

clinical indications than from its purported relationship with

homeopathy. Rigorous evidence of hormesis’s effectiveness

in even a single clinical indication would do much to extract

this field from its current state of disrepute.

Reference

Calabrese, E.J., 2005. Toxicological awakenings: the rebirth of hor-

mesis as a central pillar of toxicology. Toxicol. Appl. Pharmacol.

204, 1–8.

Menachem Oberbaum4

Noah Samuels

Shepherd Roee Singer

The Center for Integrative Complementary Medicine,

Shaare Zedek Medical Center, Jerusalem, Israel

4Corresponding author. Fax: +972 6666975.

E-mail address: oberbaum@netvision.net.il.

24 May 2005

doi:10.1016/j.taap.2005.05.011

Factors affecting the historical rejection of hormesis as

a fundamental dose response model in toxicology and

the broader biomedical sciences

Response to Oberbaum et al., 2005:

My article explored factors that may have affected the

recognition and acceptance of hormesis within the

toxicological sciences. As such, there were a variety of

factors that impacted its acceptance including the fact that

hormesis is difficult to prove because of the modest

nature of its response. This requires considerably stronger

study designs including more doses, careful spacing of

doses below the NOAEL, stronger emphasis on statistical

power considerations, temporal features as part of the

study design and greater emphasis on study replication.

In addition, toxicology has long been a high dose and

few doses discipline making hormesis little studied and,

when possibly observed, easily dismissed as random

variation. Hormesis has been further handcuffed by the

fact that as early as the 1930s, biostatistical modeling of

dose response relationships started to constrain responses

to be above background. As if these factors were not

enough of a challenge, the early and close association of

the concept of hormesis with homeopathy adversely

affected its acceptance with the pharmacology community

as a result of the longstanding and bitter feud between

homeopathy and traditional medicine from which phar-

macology and subsequently toxicology emerged. This

latter point was particularly important because leading

pharmacologists, especially Alfred J Clark, incorporated

cology 206 (2005) 365–366