A new heat flux formula valid in strong inhomogeneous laser‐produced plasmas has been derived from the Fokker–Planck equation. The nonlocal treatment of Lucianietal. [Phys. Rev. Lett.51, 1664 (1983); Phys. Fluids28, 835 (1985)] is improved by taking into account the electric potential effect. A simple and reliable phenomenological formula is proposed, which is in good agreement with numerical Fokker–Planck computations.