Analysis of biological tissue at a molecular level is of great importance in biological, medical and clinical studies. In this manuscript, we report that both plant and animal tissues can be directly ionized and analyzed by mass spectrometry under ambient conditions. By adding some solvents and applying a high voltage, spray ionization can be induced at the tip of biological tissue and a mass spectrum can be observed. Various plant and animal tissues have been tested and compounds such as lipids, alkaloids, glucosides, lignans, pharmaceuticals and proteins could be detected in the spectra. This new technique provides a simple and rapid method for tissue analysis and allows observation of compounds that cannot be detected by other ionization techniques.