Hyaluronic acid (hyaluronan, HA) is a large-molecular-weight (M_r 3–10 × 10⁶) polymer of d-glucuronic acid and d-glucosamine that is responsible for the gelling of the vitreous humor of the eye, the slippery nature of the synovial fluid, and a myriad of other functions in the body. HA is also involved in cancer metastasis, as migrating (metastatic) cancer cells emit stimuli to host cells to cause them to overproduce HA; the HA then serves as a chemical attractant for the metastatic cells, helping to establish new foci for tumor development. In a program to develop agents that intervene in this process, we have discovered a group of oligomers from HA that can be used to pharmaceutically intervene in the attachment process of metastatic cells to HA. In addition to the naturally derived ologosaccharides, we have developed a group of synthetic mimetics that are totally resistant to enzymatic breakdown in the body. Related work examines the structural aspects of these oligosaccharides, including studies by NMR spectroscopy and by ESIMS and MALDITOF MS.