Treatments are entities of central importance in many practices and applications, including both medical and technical ones. Treatments exhibit a number of intricate characteristics that give rise to practical as well as theoretical modelling challenges. One issue is that treatments can be viewed as endurants as well as events, the latter ones being temporally extended and having both a completed life history and a planned life for their future. There is also a normative relationship between a treatment viewed as an endurant and its life history. Other issues include various abstraction levels of treatments and their divisions into subtreatments. We address these issues by proposing an ontologically grounded modelling pattern of treatments based on an ontological analysis of the event notion in UFO. We also use this analysis to suggest visualizations of treatments.