According to an editorial, despite being limited by its short follow-up, the registry based cohort study provides reassuring interim evidence about the risk of cancer in patients treated with valsartan products contaminated with a probable human carcinogen NDMA. It acknowledges that the study alone cannot dispel doubts about the potential risk for patients in the longer term, but it helps inform decision making around this episode and it also illustrates the usefulness of national registries for examining the relations between risk factors and health problems and how research can give a prompt response whenever public health concerns emerge. It notes that pharmaceutical companies that had used the contaminated active substance in their valsartan medicines are now required to test samples they hold to determine the actual NDMA levels in the final products. Additional checks are being done by European official control laboratories, and other manufacturers are under investigation too.