Homeopathic use of these elements in physiological and subphysiological doses that do not exceed the concentration of the element in the body's cells and juices eliminates the risk of toxic effects. Each chemical element, along with its compounds, is present in the body at a specific concentration, ensuring its normal functioning. A persistent violation of the concentration of an element, both in the direction of reduction and in the direction of increase, is accompanied by a disease. Each element has its own pathology, for example, a lack of iodine leads to hypothyroidism with the corresponding symptoms, an excess of iodine leads to thyrotoxicosis; a lack of magnesium manifests itself in general agitation - convulsions, rickets phenomena; an excess - in general depression with lethargy, drowsiness. In homeopathy, more than 40 elements are used, which, together with their compounds, makes a figure of about 200 inorganic drugs. Naturally, studying such a large number of drug pathologies is a difficult task for a homeopathic doctor. Classifying chemical agents based on a significant common feature can greatly simplify this task. This feature is the similarity of their toxic effects. Mendeleev's table not only can facilitate the doctor's work in selecting similar-acting medications, but also indicates the directions for further research on the therapeutic effects of minerals, which is crucial for the scientific progress of homeopathy. As the toxic effects of various elements and their compounds are revealed, the significance of the periodic table will become increasingly evident. Natalya Vavilova, "Homeopathic Pharmacodynamics” (1962).