Patient financial contributions or copayments are an important funding source for access to medicine in both developed and emerging markets. In the former, they are on the rise as fiscally strapped health systems shift costs to patients; in the latter, they are declining as governments expand public funding for access. In this paper, we address three topics. First, we characterize the systems of patient contributions in eleven established markets and eight emerging markets using data from IMS and international organizations such as OECD.  We also quantify the current level of use and the trends in application of patient contributions.  Second, we conduct a systematic review of research literature on the impact of patient contributions published between 2000 and 2012 to examine if they achieve their intended policy objectives in practice. Specifically, we look at the implications of patient contributions on whether they (1) encourage responsible or rational medicine use by patients; (2) allow governments to contain public healthcare costs while still sustaining patient access to treatments; (3) provide flexible choice for patients who want to pay for non-essential or premium treatments; and (4) increase overall patient access to medicine by increasing funding for healthcare allowing public investment to focus on higher need patients, or if they tend to displace public investments thereby increasing inequity of healthcare provision. We find that in some cases, patient contributions have the desired effects, while in other cases they have limited or even opposite effects.  Whether or not patient contributions achieved desired objectives depends on the design of the policy, e.g., if these contributions discriminated between treatment choices or not. Third, based on our findings, we draw out key elements that patient contribution systems must have to achieve their objectives in developed and emerging markets.