The method of fluid loss control is provided for the case of high-rate fluid loss. Two treatment fluids are provided, where a first treatment fluid comprising a carrier fluid, solids and a first polyelectrolyte, and a second treatment fluid comprising a carrier fluid and a second polyelectrolyte. Two polyelectrolytes in both treatment fluids are oppositely charged under the pumping conditions, being taken from the classes of polyanionic and polycationic polymers. Two treatment fluids are pumped separately to the zone with fluid loss. The mixing of two treatment fluids into the well creates low-permeability agglomerates that plugs the fluid leakage channel, preventing or reducing further fluid movement between the wellbore and subterranean formation. The plugging of thief zone can be temporary or permanent.