There is a general consensus that biological fluids (serum, urines, cerebrospinal fluid) will be a treasure chest containing all possible markers of disease, albeit in much too low concentration for early detection, especially during onset of a disease. We have devised a novel, most powerful technique for bringing to the limelight the “hidden proteome”, based on a capture on hexa-peptide baits. These consist in a vastly diversified combinatorial peptide ligand library comprising millions of baits able to interact with and capture even highly dilute proteins in solution. When incubated with a complex soluble proteome, such baits can potentially carry a partner peptide ligand able to interact with each individual protein therein, based on the mechanism of affinity chromatography. Rather than acting on depletion methods, or on selecting a given population of species, via any possible pre-fractionation tool, the ligands are meant to adsorb just about any component of the proteome under analysis, by strongly increasing the concentration of low-abundance species, while drastically diluting the most abundant ones. We have had excellent results in analysis of several complex proteomes, such as egg white and egg yolk, human serum and cerebrospinal fluid, sweet whey, red blood cells, snake venoms … and many more.