Highly publicized safety issues of medicinal products in recent years and the accompanying political pressure have forced both the US FDA and the European Medicines Agency (EMA) to implement stronger regulations concerning pharmacovigilance. These legislative changes demand more proactive risk management strategies of both pharmaceutical companies and regulators to characterize and minimize known and potential safety concerns. Concurrently, comprehensive surveillance systems are implemented, intended to identify and confirm adverse drug reactions, including the creation of large pharmacovigilance databases and the cooperation with epidemiological centres. Although the ambitions are high, not much is known about how effective all these measures are, or will be. In this review we analyse how the pharmacovigilance community has acted upon two adverse events associated with the use of erythropoiesis-stimulating agents: the sudden increase in pure red cell aplasia and the possible risk of tumour progression associated with these products. These incidents provide important insight for improving pharmacovigilance, but also pose new challenges for regulatory decision making.