We studied ion transport in human jejunal mucosa under basal conditions and when tissues were stimulated electrically (EFS) and with theophylline 5 mM (N=12 pairs). Tissues were mounted in a flux chamber to measure unidirectional fluxes of²²Na,³⁶Cl, shortcircuit current, I_sc (μeq/cm²/hr), electrical potential difference, PD (mV), and total ionic conductance, G (mS/cm²). Six pairs of tissues that were normal or less inflamed responded to theophylline by increasing PD and I_sc and by reducing J_Cl(ms), the mucosal to serosal flux of Cl. In six pairs that did not respond to theophylline or to EFS, inflammation was more intense, and in the basal state, G was lower, PD was higher, and unidirectional fluxes of Na and Cl were halved. We conclude: (1) normal jejunum secretes Cl and responds to theophylline or EFS by reducing J_Cl(ms) thereby increasing Cl secretion; (2) unlike human ileum, neither theophylline nor EFS affect J_Cl(sm); (3) inflammation eliminates the response to theophylline and to EFS.