homeopathy claims a curative reaction from a small dose of a drug of which high doses cause symptoms similar to those from which the patient is suffering . homeopathy originated in 19 century , prior to the acceptance of the germ and gene bases of disease ; it has never been based on scientific evidence . results of randomized trials do not provide acceptable evidence that homeopathic treatments are more effective than placebo ; although there are also contradicting statements . it is however possible that some empirical knowledge is successfully used in homeopathy unrelated to its axioms   like can be cured with like ,   less is more    or the memory of water . hormesis has been defined as a biphasic dose - response relationship in which the response at low doses is opposite to the effect at high doses . according to this concept , however , claims that homeopathy is based on hormesis create an illusion that it employs a scientific method . the difference between hormesis and homeopathy is that hormesis can be observed at low but measurable concentrations ; while homeopathy claims effects of infinite dilutions , whereas the concept of memory of water   is used as an explanation . there is an opinion , shared by the author that the term hormesis should not be linked with homeopathy . if homeopaths have valuable empirical knowledge , it should be verified by the methods of evidence - based medicine . potentially useful empirical knowledge gathered in homeopathy , alternative or complementary medicine , should be scientifically tested and discussed in the professional literature . among the known hormetic agents are pro - oxidants , heavy metals , heat , exercise , food restriction , and different kinds of stress . living organisms come in contact with all these factors in the natural environment , so that the hormetic effects can be explained from an evolutionary standpoint . the term  hormetins  has been used in the literature for hormesis - inducing compounds . for antibiotics , hormetic effects develop secondarily along with the adaptation of microorganisms and development of antibiotic resistance . another example : thousands years adaptation of certain human populations to ethanol resulted in detectable hormesis also for this toxic agent : moderate alcohol consumption was reported to be associated with a reduced risk of coronary heart disease and other health benefits . there has been no plausible explanation of hormesis as a default principle in the pharmacological theory . scientific foundations of some hormetic mechanisms were discussed within the framework of stress response pathways . however , different kinds of stress are an integral part of the environmental impact on living organisms , who have been accordingly adapted to it . hormesis as a general principle is conceivable only for the agents that have induced adjustment of living organisms , so that a deviation in either direction from an optimum would be harmful . this is obviously the case for visible light , ultraviolet and ionizing radiation , atmospheric pressure , as well as for many chemical substances and microelements present in the environment . it is not surprising that potentially toxic heavy metals , which are present in the natural environment , act hermetically in plants . there are no general reasons to expect hormetic responses for the factors absent in the natural environment . among explanations for the hormetic effects , discussed in the literature , are an excess of repair mechanisms in response to mild damage   and a proposed existence of two receptor types ( small quantity of high - affinity receptors and large numbers of low - affinity ones ) . both hypotheses have not been sufficiently proven , in particular , as umbrella mechanisms for different types of agents . moreover , some reported hormetic effects can be doubtful because of the difficulties of differentiation between low - level hormetic and placebo effects   questionable reliability of some data , poor study designs , etc . it should be stressed that a response to an agent usually increases with increasing concentration ; in contrast , a placebo effect does not depend on concentrations , while homeopathic remedies can be extremely diluted so that the agent can be absent in the solution . for research purposes , placebo effects can be excluded in animal experiments without conditioning   and especially in plants , where hormetic effects can be studied . hormesis phenomenon was discussed in the context of homeopathy ; it was sometimes generalized and treated as a matter - of - course . for example , the question :  is hormesis likely to occur for all types of drugs ?  was answered :  there are sufficient data to conclude that the hormetic dose response is common , reproducible , and a biological expectation in the vast majority of biological systems , end points measured , and chemical classes tested . the question  may drugs be acting hormetically even though the experimental data appear inconsistent with this interpretation ? was responded :  the hormesis concept establishes a biological context for some of the key hormetic - like biphasic dose responses may represent a general biological dose - response pattern or strategy    have never been substantiated . moreover , hormesis , usually , relates to a single response , while toxic impacts can have different responses . some noxious stimuli can act synergistically with other factors , for example , on the cells with a limited or no capacity for cellular regeneration such as cardiomyocytes or neurons . it can be of particular importance in conditions when such cells are pre - damaged by ischemia so that even a mild additional damage would act according to a no - threshold dose - response pattern without hormesis . in conditions close to a functional decompensation of an organ , even minimal additional damage can be detrimental . in such conditions , which are not uncommon especially in elderly patients , the concept of hormesis can be dangerous if used in the clinical decision - making . for example , it would hardly be indicated to apply mild asphyxia in angina pectoris or small doses of ethanol in end - stage liver disease with a hope for a hormetic effect as a  general biological dose - response pattern  . considering the above , the statement :  the hormesis concept is a fundamental dose response , highly conserved , and set in an evolutionary framework    is true a priori only for the factors that have induced evolutionary adjustment . if even hormesis was observed in studies of the substances that are absent in the environment such as antineoplastic , anxiolytic or anti - seizure drugs , or resveratrol ( the latter was extensively discussed in the volume 29 of human and experimental toxicology , while relevance of the hormetic effects was questioned ) , there is still no reason to conclude that hormetic dose responses are broadly generalizable , being independent of biological model , endpoint measured , and stressor agent , and represent a basic feature of biological responsiveness to chemical and physical stressors  . the publications containing generalizations of this kind   can be cited in support of homeopathy and placebo , in gerontology and other fields of medicine , also to endorse official registration of drugs without specific effects or efficacy not exceeding that of placebo . it can pave the way for homeopathy and placebos instead of evidence - based treatments , as inexpensive substitutes , especially for elderly patients . there are many examples of marketed compounds without scientifically demonstrated efficacy , in russia often in the guise of evidence - based medications ; while artificial theoretic concepts are created to promote them . promotion of unproven health schemes can be harmful especially for elderly people . in the medical practice , deception is normally objectionable on the grounds that it limits autonomy and breaches trust ; these grounds possibly do not apply to placebos when they are prescribed within appropriate ethical limits ; although there is an opinion that clinical placebo interventions are unethical and unnecessary . if even placebo therapy with misinformation of a patient might be ethically acceptable in certain cases , it is still not a reason to publish biased information . remarkably , it seems that some patients are influenced not only by medical advertizing , which is sometimes misleading in russia , but also directly or indirectly by professional publications . in conditions when commercial considerations tend to replace medical ethics , some patients try to come clear with their ailments with the help of professional literature , which is their right . moreover , persistence and development of spurious theoretic concepts can sooner or later result in the application of invasive procedures with questionable clinical indications . for example , in the preceding article   a series of studies was commented that has become internationally known in 1986 after a publication in the lancet with participation as coauthor of the health minister of that time . there followed numerous publications in russian and foreign journals continued until today [ 40 - 47 ] ( more references are in ) . cultures of smooth muscle cells or macrophages were used for testing of blood atherogenicity , anti- or pro - atherogenic action of various substances . in addition to the drugs , many natural substances were shown by the same researchers using the cell culture method to be effective against serum atherogenicity : black elder berries , calendula and violet flowers , grape seeds and stems   etc . extracts from 13 different mushrooms were shown to significantly lower serum atherogenicity . however , as discussed in , the relationship between serum atherogenicity in a cell culture and atherogenesis in vivo must be inverse rather than direct . for example , in familial hypercholesterolemia , caused by abnormality of lipoprotein receptors , ineffective clearance of low density lipoprotein ( ldl)-cholesterol from serum causes hypercholesterolemia and predisposes to atherosclerosis . up - regulation of ldl - receptors ( and , correspondingly , of the ldl - cholesterol uptake by cells ) is one of the paradigms to the atherosclerosis therapy . accordingly , if an agent reduces cholesterol uptake by cells in - vitro , it can be expected to cause serum cholesterol elevation in - vivo . nevertheless , following their concept , the same researchers started applying extracorporeal apheresis through a column with immobilized ldl aimed at the  removal of non - lipid atherogenicity factor(s )  twice monthly for the period of 7 - 9 months . the patients were men 46 - 59 years old with functional class ii - iii angina pectoris , an angiographically documented stenosis of 2 - 3 coronary arteries and a normal cholesterol level . during this trial , the patients were reported to feel better , endure higher physical loads , and have heightened sexual activity , which could have been caused by a placebo effect . it is reasonable to assume that invasive procedures are associated with a placebo effect , which might be stronger than that of non - invasive procedures . blood apheresis is associated with certain risks , although severe side - effects such as shock or allergic reactions were reported to be very rare . efficiency of the apheresis in the study   can not be excluded , although apheresis is usually aimed at removal of lipids and lipoproteins e.g. , in patients with severe drug - resistant ldl - hypercholesterolemia or lipoprotein elevation and premature atherosclerosis . considering the above , indications to apheresis in hormesis as a general principle has never been proven as an umbrella theoretic basis for factors that are absent in the environment . if an agent is present in the natural environment , existence of its optimal level can be assumed , which would correspond to the current environmental level or , considering that the natural selection is a slow process , to some average from the past . low - dose impacts may be associated with a higher risk in a state of organ sub - compensation or failure especially in elderly patients . accordingly , practical recommendations should be based neither on the hormesis as a default approach   nor on the  like cures like ,   less is more    or other postulates of homeopathy . all clinically relevant effects , including hormetic ones , should be tested by the methods of evidence - based medicine .
homeopathy claims a curative reaction from small doses of a substance , high doses of which cause symptoms similar to those the patient is suffering from . 
 hormesis is a concept of biphasic dose - response to different pharmacological and toxicological agents . according to this concept , 
 a small dose of a noxious agent can exert a beneficial action . 
 a hypothesis is defended here that hormesis as a general principle can be assumed only for the factors present in the natural environment thus having induced adaptation of living organisms . 
 generalizations of the hormesis phenomenon used in support of homeopathy are unfounded . 
 low - dose impacts may be associated with a higher risk in a state of organ sub - compensation or failure especially in the elderly patients . 
 practical recommendations should be based neither on the hormesis as a default approach nor on the postulates of homeopathy . 
 all clinically relevant effects , hormetic or not , should be tested by the methods of evidence - based medicine .