Disclosed herein is a well treatment method comprising the steps of injecting into a well a fluid loss control agent comprising a chelating agent, a viscosity increasing agent, and a plurality of at least partially insoluble bridging solid particles dispersed therein, wherein the chelating agent is effective to at least partially solubilize at least a portion of the bridging solid particles over a solubilizing period of time for thereafter substantially dissolving the bridging solid particles, wherein the solubilizing period of time is controlled by the concentration of the viscosity increasing agent, the concentration of the chelating agent, the composition of the metal salt, the pH of the fluid loss control agent, or a combination thereof. A fluid loss control agent is also disclosed.