Vitalism is a doctrine which states that the functions of a living organism are due to a vital principle distinct from biochemical reactions. Where vitalism explicitly invokes a vital principle, that element is often referred to as the energy which some equate with the soul.

It has a long history in medical philosophies. Most traditional healing practices posited that disease was the result of some imbalance in the vital energies which distinguish living from non-living matter. In the Western tradition founded by Hippocrates, these vital forces were associated with the four temperaments and humours. Eastern traditions posited similar forces such as qi and prana. Vitalistic thinking has also been identified in the naive biological theories of children.

The notion that bodily functions are due to a vitalistic principle existing in all living creatures has roots going back at least to ancient Egypt. While vitalist ideas have been commonplace in traditional medicine, attempts to construct workable scientific models date from the 1600s, when it was argued that matter existed in two radically different forms, observable by their behavior with regard to heat. These two forms of matter were termed organic and inorganic. Inorganic matter could be melted, but could also be restored to its former condition by removing the heat. Organic compounds disintegrated when heated, transforming into new forms that could not be restored to the original. It was argued that the essential difference between the two forms of matter was the vital force, present only in organic material.

Aided by the development of the microscope in the Netherlands in the early 1600s, the germ theory of disease eventually challenged the role of vitalism in Western medicine. The cellular composition of the organs of human anatomy and the ensuing molecular analysis of the maintenance of life slowly became better understood, reducing the need to explain things in terms of mystical vital forces.

While contemporary conventional medicine has distanced itself from the less reductionistic and more vitalistic approach of traditional medicine, some areas of complementary medicine continue to espouse various forms of vitalistic concept and worldview, such as alternative medical systems or systems of therapy and practice.

The therapies that continue to be most intimately associated with vitalism are bioenergetic medicines in the category of energy therapies. This field may be further divided into bioelectromagnetic medicines and biofield therapies. Compared with bioenergetic medicines, biofield therapies have a stronger identity with vitalism. Examples of biofield therapies include therapeutic touch, Reiki, external qi and chakra healing. Biofield therapies are medical treatments in which the subtle energy field of a patient is manipulated by a biofield practitioner. The subtle energy is held to exist beyond the electromagnetic energy that is produced by the heart and brain.