What does it mean when pharmaceuticals are called ‘biologics’? This article follows a pregnant person who has been hospitalised on a Norwegian rheumatology ward after being taken off her monoclonal antibody (mab) medication. She is painfully trapped in a crisis that is medical and existential, but also epistemological. Weighing the debilitating consequences of her disease against concerns about pharmaceutical risks for herself and her unborn child, she creates and adapts her own knowledge of mabs as ‘biologics’. Far from being passively receptive, she thus becomes part of a complex project of semantics where analogies and oppositions of biologic and chemical, natural and man-made, health and unhealth work to render some knowledge plausible and some implausible. Placing the individual and the pharmaceutical label at the centre of this semantic economy, the article suggests that pharmaceutical labels play an important albeit unacknowledged role in the making of pharmaceuticals as safe and efficacious.