The purpose of this study is to compare the efficacy of Nexium® with placebo in relief of acid related pain or discomfort in the chest.

Inclusion Criteria:

• Pain or discomfort in the chest without any identifiable cause and severe enough for the patient to seek primary medical or similar care.
• History of pain or discomfort in the chest for at least the last two weeks prior to enrollment.

Exclusion Criteria:

• Signs, symptoms or relevant investigations suggestion present symptomatic coronary heart disease.
• Patients whose pain or discomfort in the chest warrants urgent cardiac investigation.