It's not the first time world leading drug makers are under fire for misconduct in the market. GSK, Lilly and Pfizer...they've all been there.

--last July, Glaxo Smith Kline agreed to pay a 3 billion US dollar Fine for the largest health fraud settlement in US history. The drug maker agreed to settle three charges of fraud brought by the U.S. FDA. GSK was accused for marketing a drug for a non-approved use. That broke the law.

--Also last year, in August, the US Securities and Exchange Commission charged Pfizer for bribery in overseas countries. The drugmaker's subsidiaries allegedly bribed doctors and other health care professionals to win business. It includes Pfizer's operations in China, Italy, Russia, and Serbia.

--Later in the year, SEC also charged Eli Lilly with similar Violations. The US drug maker is alleged to have bribed foreign government officials to win millions of dollars of business in Russia, Brazil, China, and Poland.

Pfizer hides bribery, write expenses off as marketing costs. What's more worrying for investors is the doubt this casts for the drugmakers' financial reports. Pfizer for example, hid the bribery by writing the expenses off as marketing and business travel costs.