<p></p><p>This article refers about a green method for the preparation of gold nanoparticles using juice from four types of lemon (Tahiti, Key lime, Sicilian and Rangpur). The approach is based on a classic synthesis of nanoparticles using sodium citrate as reducing agent, since all these lemon varieties have citric acid in their compositions. Several characterization techniques demonstrated the efficacy of the method for obtaining red colloidal solutions (nanoparticles in the order of 5-25 nm). The importance of this attempt to make environmentally friendly synthesis of gold nanoparticles is linked to the several applications of these nanomaterials, the most important being biomedicine, catalysis, electronics, biochemical sensing and imaging.</p><p></p