When deciding the most appropriate formulation of medication to administer to the human body, medication's physical and chemical properties, ingredients, intended use, and therapeutic objectives are considered. There are approximately 190 formulation types, including pills (tables), powders, and liquids.

Humans have various defensive mechanisms, including leukocytes, for responding to harmful external antigens like bacteria and viruses. These defensive mechanisms are referred to as the "immune system," which is designed to discriminate between "self" and "non-self" and protect normal cells within the body instead of attacking them.

The term "microbiome" combines "microbiota," meaning microorganisms, and "genome," referring to biological genetic information. It describes the microbial community residing in the human body. Microbiome treatments are therapeutics developed using these microbiota and/or their derived substances found in the human body.