Torri’r Llech (TLl) (Welsh for ‘breaking the rickets’) was a bloodletting practice which remained popular in Wales from at least the mid-nineteenth up to the mid-twentieth centuries. The practice involved cutting the ear (pinna) to induce bleeding. Indications were numerous and dynamic. Vernacular medical practices, including bloodletting, have enjoyed a long history in Wales and were influenced by a multitude of conceptual paradigms over the centuries. By drawing on original oral histories, newspaper accounts, as well as existing secondary source material, this article aims to situate TLl within the wider framework of bloodletting practices in Wales and Britain more broadly. In doing so, this paper also considers the ways in which TLl changed over time and how this dynamism proved a persistent threat to the authority of official medical institutions in Wales. By then discussing how TLl itself appeared to draw on diverse conceptual frameworks, it is argued that it may more accurately be defined as a practice within the confines of popular humoralism – a syncretic medical paradigm influenced by humoralism, astrology, Christianity, as well as local belief systems. Ultimately, TLl exhibited remarkable longevity and may have been practised as late as the 1970s–80s in parts of the Upper Swansea Valley, potentially representing the latest example of a humoral bloodletting practice native to the British Isles. This analysis challenges more linear narratives of biomedical ascendancy, showcasing how TLl coexisted with orthodox medicine in a pluralistic medical marketplace in which Welsh patients consistently exercised agency over their own care.