This paper provides a scientific foundation for the biofield: the complex, extremely weak electromagnetic field of the organism hypothesized to involve electromagnetic bioinformation for regulating homeodynamics. The biofield is a useful construct consistent with bioelectromagnetics and the physics of nonlinear, dynamical, nonequilibrium living systems. It offers a unifying hypothesis to explain the interaction of objects or fields with the organism, and is especially useful toward understanding the scientific basis of energy medicine, including acupuncture, biofield therapies, bioelectromagnetic therapies, and homeopathy. The rapid signal propagation of electromagnetic fields comprising the biofield as well as its holistic properties may account for the rapid, holistic effects of certain alternative and complementary medical interventions.