Pre-processing is a critical step in the extraction of medical information from unstructured text data. Medical text data, comprising of research articles, clinical notes, and patient records, frequently exhibit noise, variations in spelling and word forms, and other inconsistencies. Pre-processing methods are utilised to cleanse, standardise, and ready textual data for precise and significant retrieval of medical data. The goal of pre-processing is to enhance the quality of the text data by removing irrelevant elements, standardizing the representation of terms, and improving the understanding of the contextual information surrounding medical entities. By addressing these challenges, pre- processing lays the foundation for subsequent steps, such as entity recognition, relationship extraction, and data analysis, ultimately enabling the extraction of valuable insights from medical text data.