When I began fieldwork in Tanzania over a decade ago, I originally set out to observe the scientific practices through which counterfeit drugs were identified at a regional hospital in the Southern Highlands. 1 This hospital had a mini-lab for conducting a Thin-Layer Chromatographic (TLC) test, but for years lacked the iodine detection reagent needed to carry it out. Instead, I came to learn, science was happening elsewhere; not always in the laboratory or hospital, but-perhaps even more frequently-in drug shops, marketplaces, and homes. I encountered a kind of radical empiricism as my interlocutors tasted, smelled, felt, and consumed pharmaceuticals to test their qualities and discern which ones were chakachua (adulterated). Where institutionalized science has been systemically incapacitated by the logics of colonialism, neoliberalism and structural adjustment policies, debt and racial capitalism, these speculative practices are employed to enable knowledge of pharmaceutical efficacy. In this essay, I approach these embodied experiments as a form of fugitive science that also challenges the coloniality of contemporary global health and its "call to order" (Harney and Moten 2013: 131).Global health policy documents and news reports may give the impression that the category of "counterfeit drug" is rather straightforward. Such accounts provide seemingly self-evident figures like: "42% of detected cases" from 2013 to 2017 were in Africa (Cartwright and Baric 2018: 2) and "the proportion of fake pharmaceuticals in some countries can be as high as 70%" (Mwai 2020). Meanwhile, the World Health Organization (WHO) emphasizes the scale of this global health challenge, noting that: "data strongly suggest that the greater the efforts made to look for substandard and falsified medical products, the more of them are found" (WHO 2017: 12). But, subtending this framing lie assumptions about whose standards determine what is "false," "fake," or "substandard" to begin with. And, we might ask, what actually happens on the other side of this limit, as individuals engage these substances in their everyday lives? In Tanzania, I found that pharmacists routinely sell expired drugs and that some vendors also "play with" (kucheza na) the packaging of drugs; for instance, changing the listed country of origin in recognition of the fact that medicines from Europe can be sold for much more than their counterparts produced in the Global South. As these examples demonstrate, "falsified" pharmaceuticals are often partially or even wholly effective.Among my interlocutors, the Swahili neologism chakachua is used to refer to all such forms of adulteration. While other terms-like bandia and feki-translate more seamlessly into English as counterfeit and fake, the word chakachua is trickier. This term was coined during the 2010 national elections, in which much of the country argued that the results were rigged (or chakachua). My interlocuters define chakachua as "manipulation," explaining that it refers to any situation in which something's "real...