Earthing (or grounding) is the process of electrically connecting the human body to the surface of the earth. Modern lifestyles inhibit this connection, but being electrically connected to the earth is very important for our health and well-being. For this literature review, we located 14 empirical studies that used sound scientific methods for assessing the effect of earthing. These studies showed earthing improves perceptions of pain, stress, relaxation, sleep quality, mood, and general health. In addition, these studies also reported a wide variety of physiological improvements, including blood chemistry, hormone levels, nervous system activity, and immune functioning. The majority of effect sizes for all of these variables are in the moderate range (standardized mean differences between 0.25 and 0.75). Earthing has not yet been embraced by the medical community as an effective health-promoting activity, but the science behind earthing clearly indicates that it does have positive health effects.