This work assesses, by relying on methods of business history, the transformations of health policy from the end of the nineteenth century till the eve of the Second World War. The objective of this policy is to favour the access to health care of an increasing share of the population. The transformation went through two distinct stages. During the first period (1890–1914), the presence in the circles of power of supporters of social reform favoured the emergence of welfare and insurance laws. But at the end of World War One, the system showed its limitations. The public authorities then engaged in a debate on the vote on social insurance. The bill, submitted to the House of Commons, was finally passed in 1930. The Act was carried by a relatively large political majority and a small number of civil servants. This law would have undoubtedly beneficial effects on the medicalisation of French society.