CTAB (cetyltrimethylammonium bromide) and Septonex (carbethoxypendecinium bromide) are cationic surfactants known for harmful effects on different cell types (bacteria, fungi, mammal cells, etc.). Colloidal complexes of CTAB or Septonex with oppositely charged hyaluronic acid (HyA), based primarily on electrostatic interactions, were prepared with the aim to test potential modulation of surfactants cytotoxic effects. Complexes were tested for their cytotoxicity on human osteoblasts—the cell metabolic activity was determined after 24 h of treatment. Our data show that CTAB–HyA or Septonex–HyA complexes reduce (in different rate according to the used surfactant and HyA concentrations) cytotoxicity of both surfactants in all tested concentrations. In addition, a significant role of fetal bovine serum (important supplement of cell culture medium) in cell recovery under the stress conditions like CTAB or Septonex presence was observed. Taken together, HyA could be a useful modulator of CTAB or Septonex effects on cells at diverse levels. Drug or nucleic acid delivery system, diagnostic dye carriers or cosmetic industry are the possible applications of prepared complexes.