The use of plants for therapeutic purpose has a long history in many continents. However, the potential of phytochemicals, the bioactive components in the plant, in disease prevention and treatment is recognized and supported only recently by the scientific community. A lot of human diseases and health-related issues are related to the disruption of redox homeostasis by various stressors encountered constantly throughout human life. As a consequence, it leads to accumulation of abnormal proteins, inflammatory response, and oxidative stress, which are common denominators shared by many degenerative disorders. Heat shock proteins are stress proteins known to provide cytoprotection and play important roles in protein folding/unfolding. This chapter briefly describes recent findings in the effects of phytochemicals on oxidative stress-involved ischemia/reperfusion injury, obesity, and liver diseases through regulation of heat shock proteins. These phytochemicals include caffeic acid phenethyl ester from bee glue, synthetic oleanane triterpenoid CDDO-Tm, curcumin from Indian spice turmeric, resveratrol from red grapes, naringin found in grapefruit, epigallocatechin-3-gallate from green tea, anthocyanins from pomegranate, and flavonoids.