We explore care as a site of multiplicity and tension. Working with the qualitative interview accounts of nineteen health care workers in Colombia, we trace a narrative of ‘exhausting care’ in the early days of the Covid-19 pandemic. Accounts relate exhausting care to working without break in response to extraordinary demand, heightened contagion concern, the pressures of caring in the face of anticipated death, and efforts to carry on caring in the face of constraint. We bring together the work of John Law (2010, 2011) on ‘collateral realities’ with Lauren Berlant’s (2011) thesis of ‘cruel optimism’ to explore care as a site of practice in which the promise of the good can also become materialised as harm, given structural conditions. Through the reflexive narrative of ‘carrying on’ in the face of being ‘worn down’ by care, a narrative which runs through health care worker accounts, we draw attention to the collateral realities of exhausting care as personal and political, at once a practice of endurance and extraction. We argue that the exhausting care that relates to the extraordinariness of the Covid-19 pandemic also resides in the ordinariness, and slower violence, of the everyday. The cruel optimism of care is a relation in which the labour of care reproduces a harmful situation.