Amphibians are a rich source of biologically active molecules, but the majority of Toxinology scientific articles devoted themselves to investigating the anurans, given its worldwide distribution, abundance, and diversity. On the other hand, only 8.6% of Caudata species and 7.1% of Gymnophiona species have some study. This review brings the most fascinating biological activities from skin, skin secretions, and isolated components of Caudata and Gymnophiona species including taste aversion, adhesive secretion, toxic effect in animals, and cytotoxic activity as well as described molecules such as biogenic amines, tetrodotoxins, steroidal alkaloids, proteins, antimicrobial peptides, and pheromones.