A method of prophylaxis or treatment of inflammatory conditions, including, but not limited to, intestinal epithelial inflammation due to intestine-specific conditions (e.g., Crohn's disease or ulcerative colitis) or systemic causes of inflammation (e.g., endotoxemia, sepsis, hemorrhagic shock/resuscitation or pancreatitis) is disclosed. In the method of the invention, an affected patient is administered a therapeutically effective amount of a composition including an NAD-related compound, in a form that is accessible to a receptor molecule, conveyed in a pharmaceutically acceptable carrier vehicle. NAD-related compounds include nicotinamide adenine dinucleotide (NAD.sup.+), cyclic adenosine diphosphate ribose (cADPR), or functionally equivalent analogues, derivatives, metabolites or agonists thereof or prodrugs therefor.Also disclosed are ex vivo and in vivo assay methods to test candidate compounds for activity, kits for carrying out the therapeutic methods or the assay methods of the invention and articles of manufacture that include compositions for use in the methods of the invention and instructions for the use thereof.