Vasoactive intestinal peptide (VIP) is a 28-amino acid neuropeptide that belongs to the glucagon-growth hormone-releasing factor secretion superfamily. It plays a special role as it exerts potent anti-inflammatory and immunomodulatory effects. VIP is rapidly transforming into something more than a mere hormone. It’s evolving scientifically from a hormone to a novel agent for modifying immune function and possibly a cytokine-like molecule. It’s a paradigm to explore mutual interactions between neural and neuroendocrine links in health and disease. Recognition of the central functions VIP plays in cellular processes is focusing our attention on this “very important peptide” as an exciting new candidate for therapeutic intervention and drug development.