The invention includes low molecular weight, non-peptidic, non-peptidommetic, organic molecules that can act as modulators of mammalian complement C5a receptors, preferably ones that act as high affinity C5a receptor ligands and also such ligands that can act as antagonists or inverse agonists of complement C5a receptors. Preferred compounds of the invention possess some or all of the following properties in that they are: 1) multi-aryl in structure； 2) heteroaryl in structure； 3) a pharmaceutically acceptable oral dose can provide a detectable in vivo effect； 4) comprise fewer than four or preferably no amide bonds, and 5) capable of habiting leukocyte chemotaxis at nanomolar or sub-nanomolar concentrations. The invention also includes pharmaceutical composition comprising such compounds and the use of such compounds in treating a variety of inflammatory and immune system disorders.
