Generally, any technique that is used to make or modify the products of living organisms in order to improve plants or animals or to develop useful microorganisms. By this definition, biotechnology has actually been practiced for centuries, as exemplified by the use of yeast and bacteria in the production of various foods, such as wine, bread, and cheese.

However, in modern terms, biotechnology has come to mean the use of cell and tissue culture, cell fusion, molecular biology, and in particular, recombinant deoxyribonucleic acid (DNA) technology to generate unique organisms with new traits or organisms that have the potential to produce specific products. The advances and products in the biotechnology arena have been developing at a rapid pace. Some examples of products in a number of important disciplines are described below.