This article contributes to health research literature by problematizing the linear, sequential and intelligible understanding of time in the studies of illness. Drawing on the work of Martin Heidegger, it attempts to overcome the problem of considering the time of illness as either a framework controlling patients' experiences or a mind-dependent feature of their lives. The paper offers a conceptual analysis of the stories of ulcerative colitis patients from a recent clinical trial to present temporalities of illness as both objective and subjective, relational and dynamic. We attend to a combination of temporalities related to the ambiguous unfolding of illness and patients' relationships with such an unpredictable world of changing bodies, medical practices and temporal norms. Furthermore, our analysis reveals openness of times and considers ulcerative colitis patients as constantly evolving beings, with multiple possibilities brought about by illness. The paper highlights co-existence of times and considers patients' lives as incorporating a multiplicity of futures, presents and pasts. It concludes with conceptual observations about the consequences of developing complex approaches to illness in health research, which can better highlight the situatedness of patients and their multi-dimensional temporal foundations.