Drug repurposing is an effective strategy in discovering or developing drug molecules with new pharmacological/therapeutic indications. In recent years, many pharmaceutical companies are developing new drugs with the discovery of novel biological targets by applying the drug repositioning strategy in drug discovery and development program. It utilizes the combined efforts of activity-based or experimental and in silico-based or computational approaches to develop/identify the new uses of drug molecules on a rational basis. This highly efficient, time saving, low-cost strategy maximizes the therapeutic value of a drug to combat particularly, rare, difficult-to-treat diseases and neglected diseases.