With Prilosec OTC, you can take control of heartburn. If you suffer from frequent heartburn, there's no need to stash antacids everywhere for whenever heartburn might strike. With Prilosec OTC, you can take 1 PILL A DAY for 24 HOURS of ZERO HEARTBURN.Prilosec OTC is the first and original over-the-counter frequent heartburn (defined as occurring 2 or more times per week) medicine. The active ingredient in Prilosec OTC is omeprazole magnesium delayed-release tablet 20mg (equivalent to 20.6mg omeprazole), which is part of a class of medications called proton pump inhibitors, or PPIs. PPIs reduce stomach acid production by shutting down many of the pumps in the stomach that produce acid. In other words, Prilosec OTC blocks acid production at its source, so you don't get heartburn in the first place.Take Prilosec OTC once a day and use as directed for 14 days to treat frequent heartburn. Prilosec OTC may take 1-4 days for full effect. Prilosec OTC is the #1 Doctor, Gastroenterologistand Pharmacistrecommended OTC frequent heartburn medicine.