Crowdfunding for medical care is a new phenomenon but increasingly used by individuals to seek financial help to cover the costs of health care. Ethical concerns have been raised about medical crowdfunding, including implications for equity, resource allocation, medical decision-making, the promotion of non-evidence based therapies, platforms' lack of transparency and corporate interests. Medical crowdfunding efforts may point to shortcomings in health service provision, but they tend to have wider motivations and implications. However, there is no firm evidence base for establishing answers to even the most basic questions, such as who is seeking funds, for what, where and why. In this Essay, we provide an introduction to medical crowdfunding in the United Kingdom (UK). We synthesize what is currently known and the insights that might be gained from an exploratory review of 400 medical crowdfunding campaigns on the GoFundMe UK website: for instance, whether medical crowdfunding occurs in response to gaps in service provision, supports 'queue jumping' and how it relates to 'medical tourism'. We conclude with a call for research on medical crowdfunding in the UK (and elsewhere) as a means to better understand patients' perceived or actual unmet need for health and social care and inform policy development.