The metabolism of several essential elements is altered in diabetes mellitus and these nutrients might have specific roles in the pathogenesis and progress of this disease, nevertheless, the mechanisms are still far from known. Variations in Zn, Cu, Fe, Mg and Mn in rat liver have been measured both in control and diabetic rats which have been given antioxidants (either synthetic or natural extracts) or a placebo. Classical contaminant and time-consuming digestion methods for sample pre-treatment have been substituted by ultrasound-assisted liquid extraction (USLE). The effect of several parameters was studied, the best results being obtained for: 0.2 g of sample in 10 mL 10% HNO(3) and 8 min of sonication with 19 kHz frequency. The complete analytical method was validated regarding linearity, precision, accuracy and limits of detection (LOD) and quantification (LOQ). Values for LOD ranged from 0.6 for Mn to 12.5 for Mg, and LOQ ranged from 1.8 for Mn and to 62.5 for Mg expressed as microg g(-1) in sample. Results showed an increase of all the metal assayed in the liver of diabetic rats as compared to controls. Nevertheless, when animals were treated either with antioxidants or Dunaliella extracts in a short term assay, Fe increase in liver of diabetic rats was lower than with the other treatments, while Rosmarinus (rosemary) extracts were the only treatment producing a decrease in Mn on diabetic rats.