Spinacia oleracea is a leafy, green flowering plant, native to central and Western Asia. It is Caryophyllaceae, A vegetable family, Chenopodiaceae subfamily. Its leaves are a kind of common edible vegetable, which can be eaten fresh or by canning, freezing or dehydrating and then using preservation technology. It can be cooked or eaten raw, and the taste is very different. High oxalate content can be reduced by cooking.

It is an annual (rarely biennial) plant, up to 30 cm (1 foot) high. Spinach may winter in temperate areas. Leaves alternate, simple, ovate to triangular, and variable in size: 2 – 30 cm (1 – 12 inches) long, 1 – 15 cm (0.4 – 5.9 inches) wide, with larger leaves at the roots and higher leaflets on the stems. Flowers inconspicuous, yellowish green, 3 – 4mm (0.1 – 0.2in) in diameter, grow to 5 – 10mm (0.2 – 0.4in) hard, small, dry, clumped clusters of fruits at maturity, containing several seeds.

In 2017, the world's spinach output was 27.9 million tons, with China alone accounting for 92% of the total.

The English word "Spinach" dates back to the end of the 14th century and originates from the uncertain espinache (French, é Pinard).

For a long time, the common spinach S. oleracea was considered to belong to Chenopodiaceae, but in 2003, the family was merged into the family as Caryophyllaceae. Spinach belongs to Chenopodiaceae.

Spinach is an annual plant (rarely biennial), up to 30 cm (1 foot) high. Spinach may winter in temperate areas. Leaves alternate, simple, ovate to triangular, and variable in size: 2 – 30 cm (1 – 12 inches) long, 1 – 15 cm (0.4 – 5.9 inches) wide, with larger leaves at the roots and higher leaflets on the stems. Flowers inconspicuous, yellowish green, 3 – 4mm (0.1 – 0.2in) in diameter, grow to 5 – 10mm (0.2 – 0.4in) hard, small, dry, clumped clusters of fruits at maturity, containing several seeds.

In 2017, the world's spinach output was 27.9 million tons, with China alone accounting for 92% of the total.

Fresh spinach in bulk, sold in bunches or packed fresh. Fresh spinach loses a lot of nutritional value when stored for more than a few days. Fresh spinach is packed in air or nitrogen to extend its shelf life. Although cold storage slowed the effect down to about eight days, fresh spinach lost most of its folate and carotenoid content during that time. For longer storage time, it can be canned, bleached or boiled and frozen. Frozen spinach can be kept for up to eight months.

Some packaged spinach is exposed to radiation to kill any harmful bacteria. The United States Food and Drug Administration (FDA) approved the irradiation of spinach leaves, with the maximum irradiation amount of 4.0KG. However, the use of radiation to disinfect spinach is a concern as it may deplete the nutritional value of the leaves.

Researchers at the Agricultural Research Institute tested the concentrations of vitamin C, e, K, B9 and four kinds of carotenes in spinach packaging after irradiation. They found little change in the four nutrients as radiation levels increased. These nutrients include vitamins B9, e, K and carotenoid neoxanthin. This study shows that irradiation of packaged spinach has little or no effect on the nutritional value of crops, and the health benefits of irradiation of packaged spinach to reduce harmful bacteria seem to exceed the loss of nutrients.

Cadmium pollution in spinach may be very high, depending on the soil and growth location of spinach