The Azadirachta indica, which is commonly known as the neem tree, has gained prominence thanks to its wide spectrum of medicinal properties and its great potential to treat various diseases. In 1992 the US National Academy of Sciences recognized the importance of this plant and declared neem as a tree for solving global problems. The A. indica belongs to the family Meliaceae. It is a fast growing tropical evergreen tree indigenous to the Indo-Pakistan subcontinent since antiquity. The A. indica is also known as a wonder tree due to its richness in bioactive components in all parts of the tree such as the leaves, the bark, the flowers, the fruits, the seeds, the roots, and the gum oil and therefore it is highly exploitable. Over the years, a large number of diverse types of chemical constituents belonging to the various classes of compounds such as flavonoids, alkaloids, triterpenoids, steroids, carotenoids, and ketones, as well as phenolic compounds, have been extracted from the neem plant. The ultimate goal is to promote plant-derived products with the least side effects as modern drugs. In the last few decades, apart from the chemical analysis of the neem compounds, many researchers have investigated the potential of natural products as candidate medications for the treatment of various diseases. As a summary, substantial progress has been made in identifying neem-derived bioactive compounds for the development of medications for the treatment of a wide range of diseases. In this chapter, the major bioactive components of A. indica are presented along with their applications for the cure of many life-threatening diseases. © 2020 Elsevier Inc. All rights reserved.