Which of the following is NOT an indication for Omeprazole?

Omeprazole is a proton pump inhibitor primarily used to reduce gastric acid production. Its approved indications include treating conditions that involve excessive stomach acid, such as gastroesophageal reflux disease (GERD), peptic ulcers, and conditions related to acid stomach, making these options relevant.

In contrast, diarrhea is not one of the conditions for which omeprazole is indicated. Diarrhea can be caused by many factors, including infections, dietary choices, or other underlying medical issues, but it is not a condition that omeprazole directly treats. Therefore, while omeprazole is effective for reducing acid-related issues, it does not play a role in managing or treating diarrhea, which is why this is the correct answer.