BackgroundIn most societies the health marketplace is pluralistic in character, with a mix of formal and informal providers. In high-income countries, state regulation of the market helps ensure quality and access and mitigate market failures. In the present study, using Haiti as a case study, we explore what happens to the functioning of the pluralistic health marketplace in severely disrupted environments where the informal sector is able to flourish.MethodsThe overall research design was qualitative. Research methods included an extensive documentary and policy analysis, based on peer-reviewed articles, books and “grey” literature--government policy and program reports, unpublished research and evaluations, reviews and reviews from key multilateral and bilateral donors, and non-government organisations, combined with field site visits and in-depth key informant interviews (N = 45).ResultsThe findings show that state fragility has resulted in a privatised, commoditised and largely unregulated and informal health market. While different market segments can be identified, in reality the boundaries between international/domestic, public/private, for profit/not-for-profit, legal/illegal are hazy and shifting.DiscussionThe lack of state capacity to provide an enabling environment, establish, and enforce its regulatory framework has resulted in a highly segmented, heterogeneous and informal health market. The result is deplorable health indices which are far below regional averages and many other low-income countries.ConclusionsWorking in fragile states with limited capacity to undertake the core function of securing the health of its population requires new and innovative ways of working. This needs longer time-frames, combining incremental top-down and bottom-up strategies which recognize and work with state and civil society, public and private actors, formal and informal institutions, and progressively facilitate changes in the different market functions of supply, demand, regulation and supporting functions.