The article is an attempt to a comprehensive characteristic of prohibition of violations concerning a substance of fundamental rights. The prohibition is one of the conditions limiting the admissibility of such rights, as formulated in Article 19 paragraph 2 FRG Basic Law of 1949. The starting point for this analy- sis is to present the genesis of the wording of this prohibition in the constitution and to set out its functions. Another important issue taken into account in the article is to discuss the relation which exists between the prohibition of violations concerning the substance of fundamental rights and the principle of re- spect and protection of human dignity as enshrined in Article 1 paragraph 1 BL and also a relation between the prohibition of violations of fundamental rights and the provision of Article 79 paragraph 3 BL introducing „provisions relatively unchanged”. The concept of the inviolability of fundamental rights being based on the assumption that within each fundamental right it is possible to extract certain basic elements – the essence (core – the essence of the content), with- out which it could not exist and a number of additional elements – „a milieu”. While „the milieu” of a fundamental right may be a subject of interference by the legislature so far never – under any circumstances it cannot be the content of the essence of a fundamental right. The actual normative content of the prohi- bition depends on how is understood the concept of „the essence of content” of a fundamental right, which unfortunately is not uniform among the represent- atives of the German doctrine of constitutional law, nor the case law of the Fed- eral Constitutional Court of the FRG and hence a crucial part of the article is the characteristic of various theories regarding this „substance” of fundamen- tal rights.