Factors associated with environment and management and those directly related to animals, such as the health of the mammary gland, have major influence on milk quality. In dairy herds, the prevalence of mastitis can easily reach values of 70%, which causes loss of production, alteration in milk composition, increased somatic cell count (SCC) and to a lesser intensity, increased total bacterial count (TBC) in wholesale milk. The objective of the team in this project was to carry out a phase I and II clinical evaluations of a nanoencapsulated antibiotic that was developed for treating bovine mastitis. For that purpose, in vitro and in vivo essays were conducted with the new pharmaceutical formulation. The results have shown promise for the future development of a commercial product. Embrapa carried out this research project work in partnership with UFOP (Federal University of Ouro Preto) and INTA (Instituto Nacional de Tecnología Agropecuaria, Argentina).