Allegations by a whistle-blower that French pharmaceutical giant Sanofi-Aventis bribed more than 500 doctors in China in late 2007 to boost its sales are being taken "very seriously" by the company.

An anonymous whistle-blower on Thursday told the 21st Century Business Herald newspaper that Sanofi staff paid about 1.69 million yuan ($276,000) in bribes to 503 doctors at 79 hospitals in Beijing, Shanghai, Hangzhou and Guangzhou in November 2007. The company also allegedly bribed 43 doctors at five hospitals in Beijing in the form of cash payments and gifts each month from May to October in 2007.

The allegations come after four Chinese executives from British drug firm GlaxoSmithKline were detained last month for suspected bribery and tax-related violations. China's top economic planner is currently investigating 60 foreign and domestic pharmaceutical companies over their prices.