The goal of the research is to demonstrate the biological effectiveness of the Naturgard preparation on the basis of Matrine substance which is extracted from the roots of Sophora flavenscens as a potential way of the process of combating the greenhouse red spider mite of tomatoes crop in the protected areas, compared to the Insecticide Pelecol. Evaluating the obtained data it is observed that: the biological effectiveness of the Naturgard preparation after the 3rd, the 7th and the 14 days was on the average of 89% , in the case of the chemical standard (Pelecol-10,01/ha) the result was 92%. These data show that the treatment of the tomatoes crops from the protected areas with the Naturgard preparation significantly reduce the spread of the pests, although it demonstrated a biological effectiveness slightly lower compared to the chemical standard. The research of the Naturgard preparation also demonstrated that this is an ecological preparation with perspective in the plant protection system.