Abstract: In this article, we delve into how the label of ‘conspiracy theory’ was strategically used to discredit critics of Big Pharma, focusing on the case of OxyContin. Discover the manipulative tactics of Purdue Pharma, their pivotal role in the opioid crisis in the US, and the broader implications for society. Uncover the sinister interplay of discrediting opponents, redefining terminologies, and the sway of financial interests over public health.