Excipients are components that help preparing a formulation and are classified according to their purpose. Among the different classes there are the tensoactive ones which are important in various areas of industry for having a capability of generating emulsions. Polysorbate 80 and dimethyl sulfoxide (DMSO) are important tensoactives widely used by industry in different segments to favor the homogenization of immiscible substances. Thus, the aim of this study is to evaluate the antioxidant activity of polysorbate 80 and DMSO through the ability to neutralize free radical DPPH The results were analyzed by logarithmic regression curve to obtain the curve of the function and the curve of the coefficient of determination. Statistical analysis was obtained using the GraphPad Prism® software version 7.0 for Windows®. The different concentrations of polysorbate 80 and DMSO showed significant antioxidant activity in a dose-dependent manner. In this experiment, both substances exhibited antioxidant activity by scavenging free radicals by DPPH, even when used in low concentrations. These results raise concerns in the indiscriminate use of these substances in laboratory research involving antioxidant activity, since the activity can be obtained from use in experiments, DMSO or polysorbate 80. However, it has been emphasized the need for deeper studies that have higher concentrations of the substance, or using different methodologies of antioxidant analysis in vitro and in vivo, in order to establish the performance of these excipients that have a large usability in the pharmaceutical field.