During the last ten years it has been observed that a number of peptides and proteins are able to penetrate the cell membrane and enter the cell. Furthermore, it has been shown that even many cargo molecules that are covalently attached to these peptides will be translocated into the cell. Peptides that show the ability to translocate through the cell membrane are usually short peptides of less than 30 amino acids. Their only common feature appears to be that they are amphipathic and have a overall positive net charge. The exact mechanism of cell translocation is not known but appears to be receptor and energy independent, although in some cases their translocation can be partially mediated by endocytosis. The penetration into cells is usually rapid and of first-order, with half-times from 5 to 20 minutes [Zorko, M., and Langel, U., 2005].