Bacterial lipopolysaccharide (LPS, endotoxin) is the major constituent of the outer membrane of Gram-negative bacteria. LPS can cause a variety of immune- and cellular disorders that lead to lethal effects and clinical manifestations of infectious diseases. Several molecular and cellular in vitro techniques, besides synthesis of analogous molecules of the LPS active region, have provided insight in the molecular mechanisms of LPS bioactivity in cellular systems. These advances have facilitated the application of diverse LPS-based molecules in relevant areas such as vaccine technology, allergen immunotherapy, treatment of immune-related diseases/disorders, LPS-related inflammatory processes and sepsis. The purpose of this review is to examine the progress in the generation of new LPS-based molecules and their therapeutic potential.