Vital Force is an immaterial life force that is thought to be the life force that animates and controls the living organisms. It is the key to both historical vitalist philosophies and homeopathic medicine.

Concept in Vitalism
Vitalism is the belief that living things are essentially distinct to the non-living things due to the possession of non-physical vital force or elan vital. The advocates believed that chemistry and physics could not have all the answers when it comes to explaining biological processes.
It was believed to be the vital force in the following:

Regulate the shape, growth, and operations of life.

Be different, unlike all the known physical and chemical forces.

Be the initiator of life between living and non-living substance.

Empirical developments in the fields of biochemistry and cell biology validated the vitalism explanations out, overruling vital force to historical pseudoscientific explanation.

Role in Homeopathy
The vital force as defined by homeopathy represents dynamic and self-regulating energy and its presence keeps the body healthy and in balance. The founder of homeopathy, Samuel Hahnemann, referred to it as a spirit like force which animates the material body. Key tenets include:

When the vital force is in immaculate balance, there will be health.

The vital force is characterized by disturbances or imbalances and this leads to disease.

The homeopathic treatment activates the vital force by the use of remedies to bring back this balance and facilitate healing.

Mechanism of Action
The homeopathic school of thought holds that:

A cure, selected because it produces symptoms that are similar to those of the patient, induces the vital force in a gentle manner.

This is a self-stimulation of the body to heal.

The symptoms are corrected and general well-being is enhanced as the vital force is restored.

Cultural Parallels
Concepts of similar life-energy are found in other traditions of healing:

Chinese medicine: Qi

Ayurvedic medicine: Prana

Homeopathy: Vital Force

The life energy in both systems is non-material but physiological, mental and spiritual health guiding.

Key Insight: Vital force is the intangible concept believed to be the difference between living systems and dead matter, and in homeopathy, the guide to healing as it preserves or restores internal harmony.