Sea anemones have developed venom production for their survival; like all cnidarians, they store venom in nematocysts, structures distributed in different tissues of the body. The venom mainly comprises biotechnological and pharmacological interest polypeptides, such as proteases, cytolysins, neurotoxins, phospholipases, and others. Different strategies had been developed for a study from a global perspective or through classical biochemical techniques for protein study. In the present research, polypeptides in tentacles and exudate (mucus) from A. dowii were identified through a transcriptomic and proteomic analysis, identifying 261 polypeptides, such as neurotoxins that act as inhibitors of potassium (K +) and sodium (Na +) channels. Protease inhibitors, phospholipases A2, actinoporins, and other polypeptides. With classical biochemical techniques for the study of proteins, an actinoporin with hemolytic activity was identified in erythrocytes from human (HU50 = 25.6 ± 0.6 μg), sheep (HU50 = 10.7 ± 0.2 μg), goat (HU50 = 13.2 ± 0.3 μg) and rabbit (HU50 = 34.7 ± 0.5 μg). The venom presented cytotoxic activity in A549 cells (human adherent lung epithelial carcinoma), with an IC50 of (1.84 ± 0.40 μg / mL). By mass spectrometry, an actinoporin was identified. This work was supported by Programa de Apoyo a Proyectos de Investigación e Innovación Tecnológica (PAPIIT), UNAM, with a grant number IT200819.