UK-based drug maker, GlaxoSmithKline plc, or GSK, (LON:GSK) is facing a criminal investigation for bribing doctors in Poland to prescribe its asthma drug, Seretide, BBC reported Sunday. 

Eleven doctors and a regional manager have been charged for allegedly bribing doctors between 2010 and 2012 after the public prosecutor in the city of Lodz reportedly found evidence, in documents given to doctors by GSK, that the company had paid bribes in more than a dozen different health centers.

"We have evidence that in more than a dozen cases it was a camouflaged form of a bribe. In return for the financial gains the doctors would favor the product proposed by the pharmaceutical company and they prescribed that medicine," Krzysztof Kopania, spokesperson for the Lodz public prosecutor, reportedly said, according to BBC.

The company, in a statement Monday, said that its internal investigation had found that a single employee was responsible for the misconduct.

“Following receipt of allegations regarding the conduct of the programme in the Lodz region, GSK has investigated the matter, using resources from both inside and outside the company. The investigation found evidence of inappropriate communication in contravention of GSK policy by a single employee. The employee concerned was reprimanded and disciplined as a result,” the company statement said.

GSK also claims that the money it spent in Poland was for a "patient education" program but the prosecutor has argued that there is no evidence of such a program. If the bribery allegations are proved then GSK would have violated the UK Bribery Act and the U.S. Foreign Corrupt Practices Act, adding this to the corruption charges that the company is already facing in China and Iraq.

"There is a simple equation. We pay doctors, they give us prescriptions. We don't pay doctors; we don't see prescriptions for our drugs. We cannot go to doctors and say to them, ‘I need 20 more prescriptions.’ So we prepare an agreement for them to give a talk to patients, we pay £100, but we expect more than 100 prescriptions for this drug. It's a bribe," Jarek Wisniewski, a former sales representative for GSK, said according to BBC.

In 2012, GSK paid $3 billion in fines after pleading guilty to promoting two drugs for unapproved uses, and failing to report safety data about a diabetes drug to the U.S. Food and Drug Administration, making it the largest healthcare fraud settlement in the U.S. 

Last December, according to the Financial Times, GSK was accused by Chinese authorities of paying local doctors nearly $483 million in bribes by routing it through travel agencies, after which the company reportedly vowed to make major changes to its incentive schemes.

GSK's 2013 Corporate Responsibility Report shows 161 staff violations of sales and marketing practices, 48 dismissals or separations and 113 documented warnings, and a total of 375 employees were dismissed or agreed to leave the company last year alone due to various types of misconduct.

GSK’s stock fell 1.06 percent during Monday's trading session following news of the corruption charge in Poland.