The present invention relates to the use of pharmaceutically acceptable zinc salts, preferably water soluble zinc salts alone or optionally, in combination with one or more of a protein pump inhibitor (PPI), H2 blocker, anti-H. pylori antibiotic/antimicrobial, cytoprotective agent or a combination agent as otherwise described herein for providing fast action with optional long duration effect in reducing gastric acid secretion, raising the pH of the stomach during resting phase as well as decreasing the duration of stomach acid release during a secretagogue phase and for treating conditions including gastroesophageal reflux disease (GERD), non-erosive reflux disease (NERD), Zollinger-Ellison syndrome (ZE disease), ulcer disease, and gastric cancer, as well as preventing or reducing the likelihood of ulcer disease. In addition, the present methods are useful for treating patients who are non-responsive to proton pump inhibitors (PPI) and as an alternative to traditional therapies or conditions which are caused by rapid and complete inhibition of secretagogue induced acid secretion. The present invention also relates to the use of one or more water soluble zinc salts, administered in combination with a therapeutic compound or agent (second therapeutic agent) which may be delivered orally with enhanced bioavailability (compared to compounds which are administered in the absence of water soluble zinc salts) or other favorable benefits. In addition, therapeutic agents which exhibit sensitivity to low pH may be advantageously orally administered in combination with an effective amount of at least one water soluble zinc salt. Compositions according to the present invention exhibit greater bioavailability of the active agent when formulated in combination with a water soluble zinc salt in oral dosage form than when administered with the water soluble zinc salt.