Novartis Consumer Health Inc.,  one of the world's largest drug companies, announced today that it is voluntarily recalling several over-the-counter products after complaints about broken pills found in some products.

The company described the move as a precaution to strengthen its standards.

The recall follows consumers complaints of chipped and broken pills and inconsistent bottle packaging, but Switzerland-based Novartis says these issues have led to no adverse events.

The drugs being recalled are the pain reliever Excedrin and the caffeine tablets NoDoz with expiration dates of Dec. 20, 2014 or earlier, and the aspirin Bufferin, and the stomach medicine Gas-X Prevention with with expiration dates of Dec. 20, 2013 or earlier. The company says these bottles may contain pills of other Novartis products, or pills that are chipped and broken.

Novartis has suspended operations and shipments from its factory in Lincoln, Nebraska. The company said it plans to work with the Food and Drug Administration to make improvements before resuming operations.

"We are committed to a single quality standard for the entire Novartis Group and we are making the necessary investments and committing the right resources to ensure these are implemented across our entire network," said Joseph Jimenez, CEO of Novartis.