Делается залючение, что потенциал культурных и лекарственных растений в подавлении или стимулировании роста сорных видов может быть использован в борьбе с засоренностью посевов. / Using the method of biotests, the authors have studied the influence of seed exudates of medicinal plants Matricaria chamomilla L., Artemisia absinthium L., Ricinus communis L., Tanacetum vulgare L. on germination energy and morpho-physiological parameters of weed seeds under joint upswelling and germination. Inhibiting the germination energy of weed seeds by metabolites of medicinal species seeds depended on the following factors: species of both weeds and medicinal plants, structure and chemical composition of medicinal plant seeds, susceptibility of weed seeds to the exudates from medicinal plant seeds, original correlation of medicinal plant seeds and weeds during their upswelling and subsequent germination. New data have been obtained showing that aqueous solutions of root secretions of cultivated plants Lupinus albus L., Helianthus annuus L. and Secale cereal L. have inhibiting allelopathic effects on the growth of seedlings of both cultivated plants (Cucumis sativus L.) and weeds (Thlaspi arvense L., Amaranthus retroflexus L.). The effectiveness of inhibiting the growth processes was determined by a complex of internal and external factors, such as the genotype and age of donor plants, environmental conditions, the duration of their exposure to the components of root exudates and the concentration of active substances. It is concluded that the ability of cultivated and medicinal plants to suppress or stimulate the growth of weed species can be used in the fight against weed infestation.