The manufacturer of Yaz has begun airing a $20 million ad campaign aimed at correcting the “false and misleading” claims about the birth control pills it had made in previous advertisements. Bayer Pharmaceuticals began airing the ads two weeks ago following a crackdown by the Food and Drug Administration and the attorneys general of 27 states.

In October 2008, the FDA sent a warning letter to Bayer telling it to stop airing two ad campaigns for Yaz that promoted the birth control pills to treat PMS symptoms and acne. Because Yaz had not been approved to treat these conditions by the FDA, the agency said that the ads violated its rules on drug advertising.

In addition, the FDA faulted Bayer for understating the risk of side effects of Yaz. One of the hormones in Yaz—drospirenone, or DRSP—can increase the amount of potassium in the blood. This can cause blood clots or other health problems, including heart attack, stroke, deep vein thrombosis or pulmonary embolism. DRSP is also found in two other birth control pills, Yasmin and Ocella.

As part of its agreement concerning the Yaz campaign, Bayer will continue running the corrective ads until July 26, and will submit all future Yaz ads to the FDA for approval for the next six years.