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Analysis of plant materials is necessary for environmental monitoring and analytical control of food and medicinal raw materials. A study of world experience has shown that there are still no unified schemes for chemical sample preparation that are simultaneously suitable for all types of plants without limiting the range of elements to be determined. The creation of a unified scheme for plants is possible, because the macrocomposition of any plant is represented by at least 90 wt % organic compounds (fiber, protein, lipids, etc.), the mineralization of which leads to the formation of water and a gas phase. In this work, certified plant samples are mineralized in a MultiVIEW tunnel-type microwave digestion system (SPC SCIENCE, Canada) with variations in analyzed portions, composition, and volume of reagents, variants for dosing the reaction mixture, and vessel heating modes for the simultaneous determination of a wide range of elements by inductively coupled plasma atomic emission spectrometry. Assessment of the completeness of dissolution (the degree of correspondence between the found and certified contents) is used as a criterion for the optimal conditions of sample preparation. It is shown that with a three-stage mode of heating vessels (heating rate at the first stage 2.76 K/min) at a sample of 0.5 g and the separate and sequential addition of the reaction mixture (HNO3 4, H2O2 1.5, HCl 1 and HF 0.05 mL), reliable determination of typical plant contents of Si, Al, Mg, Ca, Fe, Na, K, Ba, Sr, Rb, P, B, Mn, Ti, Ni, V, Cu, and Zn is possible. [ABSTRACT FROM AUTHOR]