Norplant (R) is the brand name of the world's first registered subdermal hormonal contraceptive implant, developed by the laboratories of the Population Council, an international organisation working in the area of fertility and population growth. The article revisits the trajectory of this contraceptive in Brazil from its arrival through clinical trials to its eventual ban in 1986 by the Brazilian regulatory agency responsible for approving medications at the time. Its circulation generated controversies related to research practices, side effects and political uses of the drug as a birth control method. This article focuses its analysis on the divergences related to research practices. It uses a controversy analysis technique, reviewing the versions of those involved, investigating their understandings and the effects that this object generated in their networks. Norplant (R) provoked displacements and associations between civil society groups, State authorities, scientists and physicians, industry, pharmaceutical products, research procedures, bureaucratic instruments, and the female users of the contraceptives. Scientific styles of medical thought were shaken up and new forms of thinking about scientific autonomy began to be discussed in the country.