Three-year field research was conducted at Zawady Experimental Farm affiliated with the Siedlce University of Natural Sciences and Humanities in Siedlce. The experimental material consisted of potato tubers harvested in a field experiment set up in a split-plot arrangement with three replicates. The first experimental factor consisted of two table potato cultivars: Malaga and Oberon, and the second factor included five methods of weed control using the herbicide Avatar 293 ZC (the herbicide contained clomazone and metribuzin) and biostimulants: 1) control - without the herbicide or biostimulants, 2) the herbicide clomazone + metribuzin (Avatar 293 ZC), 3) the herbicide clomazone + metribuzin (Avatar 293 ZC) and the biostimulant PlonoStart, 4) the herbicide clomazone + metribuzin (Avatar 293 ZC) and the biostimulant Aminoplant, 5) the herbicide clomazone + metribuzin (Avatar 293 ZC) and the biostimulant Agro-Sorb Folium. Vitamin C content and total protein content were determined in potato tubers. The vitamin C content in fresh tubers was determined using the Tilman’s method modified by Pijanowski. The total protein content was calculated from the nitrogen content assayed with the Kjeldahl method and multiplied by 6.25. An application of either the herbicide alone or combined with a biostimulant contributed to a significant increase in both the vitamin C content and total protein content compared with control tubers. The cultivar Oberon revealed a higher potential ability to accumulate chemical components compared with cv. Malaga.