“Grey zone” treatments are those that rely upon the patient’s judgement of associated benefits versus harms. When clinicians judge patients are eligible for “grey zone” treatments, their acceptance should be consistent with informed patients’ values. The question is how can one obtain informed patient values? Patient decision aids (PtDAs) are interventions designed to help patients discuss treatment options with their clinicians and make specific, deliberative choices. They are used as an adjunct to counselling (not a replacement). The aim of PtDAs is to improve decision quality and to reduce unwarranted practice variations. There are over 500 PtDAs, many of which are available on the Internet.