Norberto Sotelo, Internal Medicine Head. Infantile Hospital of the State of Sonora, Mexico. I had opportunity to see by Internet the presentation about “Experience of SERTOX in spider envenenomation” (Juan Carlos Piola) in Peru, in July 2007. I observed with approval that included an appointment ours (Blak widow spider envenomation in children), Rev Mex Pediatr 2005; 72 (1): 31-35) I am thankful for this. In this occasion, I allow myself to send you the experience in our Infantile Hospital of the State of Sonora, with the desire that it will be useful to you: “Lactrodectus Mactans spider envenomation in children – Blak widow.Clinical characteristic and treatment. Gac Méd Méx Vol.142, Nº 2, 2006”. Note: we are thankful. indeed. Please, see the articles, only available in Spanish