Adult mouths may contain 500 to 1,000 different types of bacteria as part of the human flora and oral microbiology, but about 100 to 200 species may live in them at any given time. Those who care for their teeth and have a relatively clean mouth have 1,000 to 100,000 bacteria living on each tooth surface. Those that do not have a clean mouth have between 100 million and 1 billion bacteria on each tooth. Each day more bacteria grow in a person’s mouth. Though bacteria and saliva can be beneficial to one’s health, both can also cause problems. Many diseases are related to oral bacteria. While bacteria will always be in our mouths, proper oral care and habits can protect against and reduce the effects of some harmful bacteria.
Science of drugs including their origin, composition, pharmacokinetics,
pharmacodynamics, therapeutic use, and toxicology.
Pharmacology (from Greek φάρμακον, pharmakon, "poison" in classic Greek; "drug" in modern Greek; and -λογία, -logia "study of", "knowledge of") is the branch of medicine and biology concerned with the study of drug action, where a drug can be broadly defined as any man-made, natural, or endogenous (within the body) molecule which exerts a biochemical and/or physiological effect on the cell, tissue, organ, or organism. More specifically, it is the study of the interactions that occur between a living organism and chemicals that affect normal or abnormal biochemical function. If substances have medicinal properties, they are considered pharmaceuticals.