The article presents novel physicochemical data on C₆₀(OH)₂₄ aqueous solutions. Temperature and concentration dependencies of density (ρ) and speed of sound (u) and surface tension (γ) were obtained. Additionally, the study of human serum albumin (HSA) binding to C₆₀(OH)₂₄ fullerenol was conducted, and thermodynamic characteristics of C₆₀(OH)₂₄–HSA binding were calculated. The obtained values of a binding constant demonstrate that the complexes of C₆₀(OH)₂₄ with HSA are stable and HSA can perform transport functions in the bloodstream. Finally, excess thermodynamic functions of C₆₀(OH)₂₄–H₂O binary system were calculated under the application of Virial Decomposition Asymmetric Model (VD-AS) and the boundaries of diffusion stability loss were determined. Aqueous solutions of C₆₀(OH)₂₀ are thermodynamically stable up to x^diff = 6.0 · 10⁻⁵. Further concentration increase leads to formation of third-order clusters with linear dimensions of thousands of nanometres and phase separation of the aqueous solution.