The huge amount of data stored in healthcare databases allows wide range possibilities for data analysis. In this article, we present a novel multilevel analysis methodology to generate and analyze sequential healthcare treatment events. The event sequences can be generated on different abstraction levels automatically from the source data, and so they describe the treatment of patients on different levels of detail. To present applicability of the proposed methodology, we introduce a short case study as well, in which some analysis results are presented arising from the analysis of a group of patients suffering from colorectal cancer.