Background & Aims: During acute exacerbations of inflammatory bowel diseases, oxidants are generated through the interactions of bacteria in the lumen, activated granulocytes and cells of the colon mucosa. In this study we explored the ability of one such class of oxidants, represented by monochloramine (NH₂Cl), to serve as agonists of Ca²⁺ and Zn²⁺ accumulation within the colonocyte. Methods: Individual colon crypts prepared from Sprague-Dawley rats were mounted in perfusion chambers after loading with fluorescent reporters fura-2AM and fluozin-3AM. These reporters were characterized, in situ, for responsiveness to Ca²⁺ and Zn²⁺ in the cytoplasm. Responses to different concentrations of NH₂Cl (50µM, 100µM, 200 µM) were monitored. Subsequent studies were designed to identify the sources and mechanisms of NH₂Cl-induced increases in Ca²⁺ and Zn²⁺ in the cytoplasm. Results: Exposure to NH₂Cl led to dose-dependent increases in [Ca²⁺]_I, in the range of 200 to 400 nM above baseline levels. Further studies indicated that NH₂Cl-induced accumulation of Ca²⁺ in the cytoplasm is due to release from intracellular stores, as well as basolateral entry of extracellular Ca²⁺ through store operated channels. In addition, exposure to NH₂Cl resulted in dose-dependent and sustained increases in [Zn²⁺]_i in the nanomolar range. These alterations were neutralized by dithiothreitol, which shields intracellular thiol groups from oxidation. Conclusions: Ca²⁺ and Zn²⁺-handling proteins are susceptible to oxidation by chloramines, leading to sustained, but not necessarily toxic, increases in [Ca²⁺]_i and [Zn²⁺]_i. Under certain conditions, NH₂Cl may act not as a toxin but as an agent that activates intracellular signaling pathways.