This paper analyses our experiences of conducting participatory action research into alcohol abuse in communities living with bonded labour in Tamil Nadu and in Bihar. The action research on alcoholism in these communities is part of a large-scale mixed-methods qualitative and quantitative participatory research programme which was designed to encourage community-based solutions to bonded labour in India. The research was conducted in two 'slavery hotspots', both with a high prevalence (over 50%) of households with people in bonded labour, as part of a multi-million dollar programme of interventions funded by a foundation specialising in modern-slavery eradication. The programme focuses on workers in brick kilns and stone quarries and, to some extent, on sex workers in Bihar and Uttar Pradesh, and on cotton-mill workers in Tamil Nadu. The participatory research runs in parallel to programme interventions by local NGO's. This paper examines whether participatory action research methods can transform violent, stigmatising approaches to alcohol consumption in marginalised communities into community-owned, evidence-informed, non-violent harm reduction approaches. In both locations alcohol consumption is a highly stigmatised public secret. Bihar has banned alcohol production and consumption.