Fluid loss during drilling operations has a very significant effect on both reservoir formation damage and monetary terms. There are many additives to control this unwanted phenomenon. Nevertheless, most of these substances are artificial chemicals. Thus, they are not only expensive, but also hazardous to the environment. In this article, a more natural method was applied to overcome the higher filtration problems by employing carboxyl methyl cellulose (CMC) and polymers (XT), DSHV, and MAC PR. Drilling fluids were prepared due to American Petroleum Institute (API) standards. The fluid weights were adjusted as 9 ppg. API filtration tests were applied to fluid samples including the chemicals. Tests were also conducted with non-treated bentonites + barite fluids without chemicals for comparative purposes. All of the rheological parameters including plastic and apparent viscosity and yield points were determined. Comparative graphs of shear stress vs. shear rates were plotted. The optimum CMC and polymer amounts were selected by graphical analysis of the results of rheological tests made by using shear meter and filtration tests. An optimization of the fluid loss control due to addition of the chemicals was made. The behavior of water-based fluids with CMC and polymers was examined. The accurate and sensitive industrial application of this study would reduce drilling fluid loss expenditures effectively.