The studies were conducted in 2010–2011 at the Research Institute of Horticulture in Skierniewice. The aim of the research was to determine the nature and degree of damages and histological changes in celeriac caused by herbicides that are not recommended for application in this crop, such as: bromoxynil, clopyralid, fluroxypyr, MCPA and tribenuron methyl. The herbicides were applied 2–3 weeks after transplanting in the field experiments and in the greenhouse tests at 3–4 leaves stage of celeriac. The herbicides were used at the maximum recommended doses allowed in cultivation of other plant species or reduced to 10 and 2%. Phytotoxicity of herbicides to celeriac was determined during the experiments. The height and biomass of celeriac leaves were measured in the greenhouse tests. Plant material, which had been collected from the experiments, was subjected to macroscopic observation regarding morphological changes of leaves, and microscope evaluation of damages caused to leaf tissues. It has been proved that the examined herbicides can cause damages to celeriac and degree of damages depends on herbicide dose. Clopyralid, fluroxypyr and tribenuron methyl used at the highest doses caused higher crop damages than bromoxynil and MCPA. The symptoms were also observed during histological analysis. High damages of above ground parts of celeriac decreased yields in particular after application of tribenuron methyl and fluroxypyr.