In conditions of chemical pollution, it is relevant to enhance the resistance of plants with substances that have a protective action. The effect of humic substance Lignohumate on the phytotoxic properties of phosphorus-containing compounds methylphosphonic acid (MPA) and sodium pyrophosphate (SPP) was studied in model experiments. Lignohumate was tested at three concentrations (0.1, 0.5, and 1 g/L) on Hordeum distichum L. of the Novichok variety. The test functions were such indicators as the germinating and sprouting ability of seeds, the growth and biomass accumulation of seedlings, and the inhibition effect. Lignohumate in the studied concentrations did not affect germination of the barley seeds, but it stimulated growth of the barley seedlings. In the conditions of MPA pollution (0.01 mol/L), Lignohumate exerted a protective effect on the plants, and the highest concentration of humic preparation (1 g/L) was the most effective. In the experiments with SPP (0.01 mol/L), Lignohumate stimulated germination the barley seeds but it did not reduce the growth inhibitory effect of SPP. The combined exposure to the studied pollutants negatively affected growth and accumulation of biomass by the barley roots. The introduction of Lignohumate weakened the combined effect but could not completely countervail it. The calculation of inhibition effect showed that the phytotoxicity of phosphorus-containing substances reduced in the order MPA (without buffer) - SPP - MPA (with buffer) - MPA+SPP . The introduction of Lignohumate to the growth medium was the most effective in experiments with low-toxic substances.