Despite momentous breakthroughs in unraveling the pathophysiology of many chronic conditions and developing novel therapeutic agents, everyday clinical practice is still fraught with inadequate or inappropriate use of treatments with proven benefits. Aspirin is a paradigmatic example, as it is used for the primary and secondary prevention of cardiovascular disease and appears to have a beneficial impact on cancer risk. Yet, underuse, non-compliance or cessation of aspirin are not uncommon, may have an important clinical impact, and are not aggressively prevented or managed. Increasing the awareness of the extent and impact of aspirin underuse, non-compliance or cessation, and intensifying efforts at preventing them are worthy goals likely to yield significant benefits on cardiovascular morbidity and mortality worldwide, and possibly also on cancer outcomes.