Phytochemical study of medicinal plants is essential to determine the presence of active constituents in them. Alkaloids, the largest class, are the most important from medicinal point of view. Alkaloids are low molecular weight nitrogen containing compounds and are typically alkaline. Approximately more than 2000 alkaloids have been isolated so far. They are found in those plant parts where there is great vitality and growth. The medicinal use and their biological source along with family has been discussed in their review.