Ecdysteroids are known as insect moulting hormones. They have the basic steroid structure, although their physiological effects on mammalians do not show the thymolytic and androgenic side effects of vertebrate type steroid hormones. At the same time, phytoecdysteroids can be used utilizing their anabolic and adaptogenic effects. Ecdysteroids also have a tremendous potential in the most modern therapy. Recently, the biotechnology started to employ ecdysteroids as powerful inducers for gene-switch systems with insertion of modified insect receptor into the malignant cells. Nineteen ecdysteroids were isolated with combined chromatographic methods from the herbs of Silene italica ssp. nemoralis (Waldst. and Kit.) Nyman. The chemical structure of the isolated compounds have been elucidated using spectroscopic methods (x-ray, UV, CD, IR, MS, 1D-, 2D-NMR, HMQC, HMBC, COSY, TOCSY, NOESY, ROESY). Structural determination of two of the five new ecdysteroids is detailed here.