UV-B is a growing concern due to the rise in UV-B levels on the surface of the earth as a result of the loss of stratospheric ozone. Increased levels of UV-B radiation can in fact negatively alter plant physiological processes, growth and productivity. However, when researching the effects of UV-B on medicinal plants like Phyllanthus amarus and in the tropical area under field conditions, there are some curious phenomena have been discovered. Enhanced UV-B radiation has greatly improved the growth of P. amarus. The outcome of the photosynthetic pigment showed increased UV-B enhanced synthesis of Chlorophyll or the accumulation of Chlorophyll pigments in the treated plants compared to non UV-B treated plants. The concentration of UV-B absorbing pigments also increased due to enhanced UV-B radiation in P. amarus. The synthesis of secondary metabolites such as flavonoid and phenol content was increased under UV-B treatment as compared to control. The UV-B radiation enhances the grade of the medicinal plant by improving the medicinally active compounds. This enhanced impact of UV-B could be important to observe when studying the phytotherapeutic function of P. amarus in health aspects of human life.