Tityus serrulatus (Ts) venom is composed of a mixture of toxins presenting diverse biological functions. However, although this venom has been studied over the past three decades, omics analysis revealed that most of its toxins are not identified or their biological activities are unknown. Ts19 Frag-II is included in this group, which function is still uncertain. This study aimed to expand the biological activities of Ts19 Frag-II through in vivo investigation. Our results demonstrates that mice challenged with Ts19 Frag-II presented biochemical alterations, increasing serum levels of urea, ALT and b-globulin, besides decreasing g-globulins. Moreover, this toxin was also able to induce immunological alterations, increasing NO, IL-6, TNF-a and IL-17, being considered a proinflammatory toxin. The increase of IL-17 was unprecedented regarding Ts toxins and could be a result of the overall produced-effect of cells of innate immunity cells (neutrophils, monocytes, natural killers and lymphoid tissue inducers – LTis) as well as of adaptive immunity (Th17 cells). This study expanded the biological activities of Ts19 Frag-II, suggesting that this toxin could be contributing to the Ts envenoming through alterations of biochemical parameters as well as triggering the inflammatory response.