How does FDA determine if a company is complying with cGMP regulations?

FDA inspects pharmaceutical manufacturing facilities worldwide using scientifically and cGMP trained individuals, whose job it's to evaluate whether the company is following the cGMP regulations. FDA also relies upon reports of potentially defective drug products from the public and the industry. FDA will often use these reports to identify sites for which an inspection or investigation is needed. Most companies that are inspected are found to be fully compliant with the cGMP regulations.