Background/Objectives: This paper gives an overview of some tasks involved in the retrieval process, corpus and resources of medical information retrieval. Methods/Statistical Analysis: Inverted file representation method is used in the retrieval process for associating documents in the corpus with various search terms. Conventional statistical ranking functions such as Jaccard, Okapi and Euclidean have been widely used for ranking retrieved medical documents. An extractive informative generic mono-lingual single-document summarizer is used to produce medical domain-specific summary. Sentence ranking method is used to include most appropriate sentences in the final summary. Findings: Studies reveal that people are searching the web and read medical related information in order to be informed about their health. In the medical domain, richest and most used source of information is MEDLINE. Because of frequent use of acronyms in the medical literature, using the term that appears in documents as keywords for document indexing would not be effective. Also, using Bag of Words representation could not capture the semantic meaning of terms. Some domain-specific thesauri like UMLS, MeSH and Gene ontology are available for biomedical retrieval. These domain-specific thesauri can provide synonyms, hypernyms and hyponyms of a specific term but it does not look into the context. Therefore, the retrieval results of using domain-specific thesauri are somewhat conflicting. It is possible to identify which lexical variant of specific term should be used under specific context by using Wikipedia as resource for biomedical retrieval. Conventional ranking functions fail to capture the inherent features of natural language text. Evolutionary algorithm based ranking can enhance the retrieval performance. Any domain-specific summarizer must consider similarity between sentences as essential feature for summarization. Applications/Improvements: Improvements in retrieval results is achieved by using context-aware keywords as indexing keywords and highly robust hybrid evolutionary algorithm based ranking function for ordering the retrieved documents.