Phytoalexins are a defense group and are low molecular weight compounds of antimicrobial nature produced by plants in response to attacking pathogens. Phytoalexins are considered diverse in their chemical nature, but have a common function, that is, the defense of the plant. With climate change and the development of pure-line crop varieties, the properties of phytoalexins are the accumulation at the sites of infection and inhibit the growth of pathogenic microbes making them potential antimicrobial agents, which may be exploited to resist the disease. Since many genes that encode enzymes involved in their biopath are well studied, phytoalexins are also useful in promoting human health. Some of them are known to possess various biologically active properties such as antioxidants, anticancers, antidiabetic, anti-paratopia, heart and growth preparation.