This paper describes a new approach of data retrieval from free text documents in medical domain. Proposed approach creates the document summary and highlights most important keywords in the text by means of document ontology, as an internal representation of the document. This document ontology is a graph with concepts, relations between them, and concept points as a metric of relevance. By means of points the approach performs ambiguity resolution, selects most relevant concepts to display in the summary, and votes for keywords highlighting in the text. Moreover, interactive highlighting reveals additional information from document ontology as reader interacts with the keywords and summary in the document. The described approach helps to speed up analysis and decision-making processes by means of providing aggregated summary for a document and highlighting most meaningful parts of the text.