Many copies of a single plant can be grown using the plant tissue culture technology. These copies have the right characteristics to satisfy medical and nutritional demands. Secondary metabolites are purposefully synthesized by using the in vitro technique. These metabolites act as protectors for plants during stressful conditions and offer resistance against different organisms and factors, ultimately helping the plant to survive. With the passage of time, the development of new instruments for the improved synthesis of secondary metabolites via the genetic control of biosynthetic pathways has been aided by the speedy development of recombinant DNA technology. Plants generate a wide range of secondary metabolites that have various biological functions, such as fungicide, herbicide, anti-parasitic, and anti- microbial functions. Nanotechnology has the potential to drastically alter conventional plant growing methods and bring about the synthesis of flavonoids, anthocyanin, and diosgenin by using silver nanoparticles and cadmium oxide nanoparticles (CdONPs). The technique of callus cultures is increasingly utilized to produce secondary metabolites. Hence, the main objective of the current review is to increase the synthesis of secondary metabolites.