EZ-MUD® GOLD EU Clay and Shale Stabilizer provides inhibition of clay and shale formations in water-based drilling fluids without substantially increasing viscosity. EZ-MUD GOLD EU Clay and Shale Stabilizer, when added to a TUNNEL-GEL® PLUS or BARO-GEL® slurry, yields an inhibitive drilling fluid system while maintaining manageable and effective fluid properties. EZ-MUD GOLD EU Clay and Shale Stabilizer can be mixed easily at minimal shear thereby eliminating the need for liquid emulsions.