So far, the main sources of biologically active substances used in medicine have been plants, molds, and propolis. The obtained compounds have either therapeutic features or require additional modification. They are sometimes combined with other pharmacological substances to intensify their therapeutic effect. However, the effectiveness of many drugs has been rapidly decreasing.The overuse of antibiotics in the treatment and prophylaxis of human infections (especially in hospitals) as well as their widespread and often unjustified use in the treatment and prophylaxis of farm animal illnesses contribute to the development of a variety of resistance mechanisms by microorganisms. Because of the increasing ineffectiveness of antibiotics used so far and difficulties in obtaining new drugs, it is necessary to find new sources of these compounds, for example in animal organisms. Research has demonstrated that amphibian skin secretions are rich in a variety of active substances which have strong pharmacological properties. In these compounds we can distinguish, for example, toxins, antimicrobial peptides, opioid peptides, steroids, and alkaloids.These compounds show cytotoxic, antimicrobial, analgesic, anti-inflammatory, and even antiviral activities (including anti-HIV). These substances can be used in cell receptor studies and in transmembrane ion transport analysis. Because these compounds are secreted by skin glands,they can be easy obtained without injuring these animals. It is probable that amphibian skin constitutes a potential source of modern drugs.