Mikania glomerata Sprengel, Asteraceae (guaco), is traditionally used against cough as an infusion, a fluid-extract, a tincture or a syrup. The present investigation had as objective the development of a sugarless pharmaceutical liquid form to carry the guaco fluid extract, a substitute to the guaco syrup, it would specially help those who cannot ingest the glycogenic substances found in syrups. Liquid formulation was developed, in which the preservants concentration, the humectants agents, and sweeteners and flavors were defined, thickening polymers commonly used in technological processes in order to reduce the syrups viscosity were tested. The rheological behavior was analyzed and the preliminary evaluation of physical characteristic was done. Of all the tested polymers, the sodium alginate (1%) showed itself the most stable, regarding the analyzed parameters. It had a rheological behavior similar to the Newtonian fluids and has adequate pH of oral use, as well as compatibility to the fluid guaco extract.