Biological active food components comprise a wide range of chemical compounds displaying different structures and physico-chemical properties. The most part of biological active compounds is found in vegetal food. The biological active substances play a vital role in the prophylactic of the fundamental chronic diseases and health maintenance, though they are not essential food compounds. The commonly used n medicinal practice vegetables, that contain fitantid, are onion, garlic, horseradish and so on. Fitocompounds are biological active natural organic compounds which are a component part of vegetal products. In plants these substances act as protection agents against infections as well are responsible of color, flavor, and taste. Fitocompounds food sources are vegetables, fruits, beans, cereal products, walnuts, seeds, mushrooms, and spice. Drying or dehydration is the most healthy and effective way for a long-term conservation of plant and animal products without altering the nutritional and organoleptic qualities. Vegetables and fruits are dehydrated to be consumed all year round. Permanent increase of the market demand of these products requires developing of new methods of drying, which would ensure a high quality of the final product. Samples of mushrooms (champignions) and horseradish roots were treated with over-current frequency for this purpose. The properties of the material subjected to drying have been studied by means of complex thermal analysis (thermogravimetry, differential thermogravimetry, thermography and differential thermal analysis). It has been established that the thermolysis of samples occurs in three or four stages. The first stage-dehydration - takes place with a mass loss from 3 up to 6% in the temperature range 70-100°C (the mass of remaining water is diminishing by 15-30 times). By means of Horowitz-Metzger-Topor [1-2] method the characteristics of kinetic parameters (reaction order, activation energy, velocity constant and process entropy) that describe the stage of dehydration of plant products dried in different conditions, has been calculated. The investigation results demonstrated that the reaction order values of the dehydration stage are included in 0.5-2.0 range, indicating the complexity of the processes: e.g. occurring in several separate stages. The value of activation energy varies in 20-80 kJ/mol domain depending on drying conditions and are close both for mushrooms and horseradish roots samples. The dependence activation energy - temperature has been determined for mushrooms and horseradish roots samples. A minimum value at t = 70-80°C on the Ea = f(t) dependence curve has been recorded. As the treatment time increase and temperature reaches the value of 80°C, a decrease of activation energy has been observed. This fact was explained by the elimination of the “non-bonded water” from the system. The follow-on increase of the activation energy was put down to the increase of the energy required for the “bonded water” elimination. An inverse dependence of activation energy from sample treatment time has been determined. The optimal temperature for getting products with longest storing period was found to be t= 70-80°C.