Background Carboxytherapy is capable of inducing tissue repair which results in an increase in elastic and collagen fibers. Objectives To evaluate the effects of carboxytherapy upon human skin collagen and elastic fiber synthesis. Methods Case study of nine volunteers who received a single application of carboxytherapy in the left infraumbilical region, with infusion rate of 100 mL/min and 0.6 mL/kg weight over an area of 25 cm2. After 60 days on average, the skin was collected for histological analysis and stained with picrosirius red for collagen and Verhoeff for elastic fibers. The percentage of fibers found was marked by the Image J® program and recorded in a Microsoft Excel spreadsheet. Statistical analysis was performed using SPSS (version 20), with a significance level of 95%. Results An increase in the collagen and elastic fibers sample was observed in the treated group. Morphometrically, a significant increase in the percentage of collagen in the Carboxytherapy group (41.44 ± 4.50%) was observed compared with the control group (37.44 ± 3.87%) with P = .04; for elastic fibers, the percentage showed no significant difference between the control group (10.55 ± 4.33%) and the carboxytherapy group (10.44 ± 3.71%). Conclusions Carboxytherapy with the parameters used in this study was able to stimulate collagen and elastic fiber synthesis, with significant differences in the morphometry for collagen fibers.