Phytochemistry is the study of phytochemicals, which are chemicals derived from plants. Specifically, phytochemistry describes the large number of secondary metabolic compounds found in plants. Many of these are known to provide protection against insect attacks and plant diseases. They also exhibit a number of protective functions for human consumers.

Phytochemistry is a peer-reviewed scientific journal covering pure and applied plant chemistry, plant biochemistry and molecular biology. It is published by Elsevier and is an official publication for the Phytochemical Society of Europe and the Phytochemical Society of North America.