Recurrent mood disorders can have devastating long-term effects, and the cost of these illnesses in terms of human suffering, productivity and health care is enormous. It is now recognized that, for many patients, the long-term outcome is often much less favorable than previously thought, with incomplete inter-episode recovery, and a progressive decline in overall functioning observed. Indeed, according to the Global Burden of Disease Study, mood disorders are among the leading causes of disability worldwide, and are likely to represent an increasingly greater health, societal, and economic problem in the coming years. Dietary and nutritionally derived botanical compounds offer promise both for experimental therapeutics of complex diseases and for chemoprevention of illnesses such as depression.