This thesis breaks away from the prevailing notion of unani tibb as a 'system' of medicine by drawing attention to some key arenas in which unani practice was reinvented in the early twentieth century. Specialist and non-specialist media have projected unani tibb as a seamless continuation of Galenic and later West Asian 'Islamic' elaborations. In this thesis unam tibb in early twentieth-century India is understood as a loosely conjoined set of healing practices which all drew, to various extents, on the understanding of the body as a site for the interplay of elemental forces, processes and fluids (humours). The thesis shows that in early twentieth-century ummtibb the boundaries between humoral, moral, religious and biomedical ideas were porous, fracturing the realities of unani practice beyond interpretations of suffering derived from a solely humoral perspective. The principal objective of the thesis is to draw attention to the tensions manifest in different spheres of unani practice as certain practitioners reconfigured their knowledge and practices though the prisms of nationalist and communitarian politics, changing social and moral norms, the expanding use of print and colonial inspired models of legitimacy. These phenomena presented challenges to the authoritative practice of tibb as a local, family affair. Unani practitioners were forced to take stock of what they thought to be good, authentic and legitimate in order to represent this knowledge to the public on a vastly new scale; both to gain and maintain their trust and their custom, and in order to represent the credibility of their practices in new, less personalised administrative, judicial and political domains. The thesis emphasises the importance of the market in the reform of tibb during this time, an area which is especially important in the context of the collapse of courtly patronage for elite unani practice in most parts of India during the nineteenth century. The principal themes framed in this study are: plague and unani reform; legitimacy in relation to institutional and family practice; the emergence of Ubb as a 'national' enterprise; new engagements with women and change in the treatment of certain women's diseases; conceptualisations of male sexuality; and the role of the unani journal in the establishment of innovative practices and relationships with the public.