This is a multicenter, double-blind, randomized, placebo-controlled study to investigate the safety and efficacy of rabeprazole 10 mg in treating frequent heartburn. The study will last for up to five weeks and consists of the following three phases: a one to two week screening period that includes a one-week, single-blind, placebo run-in phase, a two week double-blind, randomized treatment phase, and a one week single-blind, placebo follow-up phase.

Inclusion Criteria:

1. Male or female patients > 18 years of age.

2. If female, not of childbearing potential by reason of surgery or menopause, or of childbearing potential, but using an approved method of contraception since the last menstrual period. Females of childbearing potential must have a negative serum pregnancy test before starting the study.

3. Patients must report a history of heartburn at least two days per week over the past month.

Exclusion Criteria:

1. History of erosive esophagitis verified by endoscopy.

2. History of gastroesophageal reflux disease (GERD) diagnosed by a physician.

3. Patients who have a history of Barrett’s esophagus or esophageal stricture.

4. Evidence of any medical condition that may interfere with the conduct of the study, the interpretation of study results, or the health of the patient during the study.

5. Patients who require continuous use of proton pump inhibitors, histamine receptor (H2) blockers, or prokinetics. Prior intermittent use of these agents is permitted if they are discontinued at least three days prior to the run-in phase. The H2 blocker, cimetidine (Tagamet��), must be discontinued for at least seven days before the study drug is administered.