Plant oils are an essential part of food production and cooking in general; edible oils are found in soybeans, corn, peanuts, and other types of seeds and vegetables. Traditionally, the process of extracting these oils was tedious and had to be done by hand; the seeds were ground into a powder, which was heated, then pressed in order to release the oils. Oils today are often extracted by mechanised equipment using chemicals. Oil mills, oil extraction machinery and equipment make the mass production of edible oils possible.

Vegetable oil, which is mostly made of soybeans (sometimes corn), is the most commonly produced type of edible oil. The extraction process the seeds go through is similar to the traditional method, only on a much larger scale, using large machines. Oil is extracted either chemically using petroleum based hexane, or by pressing using large machines.

Other seeds commonly used for edible oils include sunflower, rapeseed, and corn. Plants and trees that produce oils (edible and non-edible) are olive and tea trees, and many different types of herbs, which are used for perfumes or as essential oils.

The movement of oil production from small, less efficient manufacturing operations to larger and larger oil mills, many using computerised machinery, has made several positive contributions to Indian society. These plants have brought employment and growth to many places that previously were considered to be relatively isolated. As technology continues to improve production methods, it may even be possible that some oils could be used as an alternative to petrol.