Medicines of uncertain quality, safety and efficacy can be worse than no treatment at all. It is the responsibility of national medicines regulatory authorities to protect patients from harm. Yet, there are great disparities in regulatory capacity globally, preventing large populations from accessing the benefits of advances in the pharmaceutical field. This article describes the main regulatory functions and how they are applied to assure the quality, safety and efficacy of different types of medicines in different environments. It gives examples of initiatives that have increased access to good quality medicines worldwide and - more importantly - are laying the groundwork for collaborative approaches aiming to ensure that pharmaceutical products meet the same, stringent quality standards in all parts of the world.