One of its offices was visited at the end of last month to investigate a potential case of "unfair competition", Bayer HealthCare said in a statement to AFP.
China is mounting a sweeping probe into foreign pharmaceutical firms, accusing some of abusing their monopoly positions to boost prices unfairly.
Police are also investigating Britain's GlaxoSmithKline (GSK) over allegations employees gave bribes to sell its products.
Authorities have detained at least four GSK executives in the case, while state media has alleged the firm was responsible and not just individual employees.
Bayer said it was visited by officials of a branch of the State Administration for Industry and Commerce, which handles market supervision and regulation. It did not identify the location.
The company said it had strict compliance rules in place and would investigate allegations of violations of its policy by employees.
US drugmaker Eli Lilly and France's Sanofi have both come under scrutiny after anonymous whistleblowers cited by Chinese state media claimed that employees paid bribes.
Eli Lilly said it was investigating, while Sanofi said it was taking the claims "seriously".
Chinese authorities are investigating other industries over pricing, state media has reported, with the moves sending a chill through the foreign business community in the country.