To answer your questions:
1) Improvement from gastritis can take in the order weeks. It can vary from patient to patient.
2) If the aspirin is leading to the gastritis, taking it in conjunction with omeprazole may be needed. Another option to be explored is taking the aspirin with food, or changing to Plavix.
These options can be discussed with your personal physician.
This answer is not intended as and does not substitute for medical advice - the information presented is for patients education only. Please see your personal physician for further evaluation of your individual case.
Kevin, M.D.
www.kevinmd.com