The pistachio (/pɪˈstɑːʃi.oʊ, -ˈstæʃ-/ pih-STAH-shee-oh, -⁠STASH-;[2] Pistacia vera), a member of the cashew family, is a small to medium-sized tree originating in Persia.

[4] In 2022, world production of pistachios was one million tonnes, with the United States, Iran, and Turkey combined accounting for 88% of the total.

[9] Pistachio trees are fairly hardy in the right conditions and can survive temperatures ranging between −10 °C (14 °F) in winter and 48 °C (118 °F) in summer.

Pistachio trees do poorly in high humidity conditions and are susceptible to root rot in winter if they get too much water and the soil is not sufficiently free-draining.

[16] The earliest evidence of pistachio consumption goes back to the Bronze Age Central Asia and comes from Djarkutan, modern Uzbekistan.

[22] The early sixth-century manuscript De observatione ciborum (On the Observance of Foods) by Anthimus[23] implies that pistacia remained well known in Europe in late antiquity.

[24] Archaeologists have found evidence from excavations at Jarmo in northeastern Iraq for the consumption of Atlantic pistachio.

[16] The Hanging Gardens of Babylon were said to have contained pistachio trees during the reign of King Marduk-apla-iddina II about 700 BCE.

[16] In the 19th century, the pistachio was cultivated commercially in parts of the English-speaking world, such as Australia and in the US in New Mexico[9] and California, where it was introduced in 1854 as a garden tree.

[25] In 1904 and 1905, David Fairchild of the United States Department of Agriculture introduced hardier cultivars to California collected from China, but it was not promoted as a commercial crop until 1929.

[29] The Shah was forced into exile in January 1979 during the Iranian Revolution, resulting in an end to trade between the United States and Iran, providing additional incentives for American farmers to plant dramatically more pistachio trees.

At that time, pistachios were Iran's second-most important export product, after the oil and gas sector.

[30] By 2020, there were 150,000 pistachio farmers in Iran, approximately 70% of whom were small-scale producers using inefficient manual picking and processing techniques.

[31] Pistachio trees are vulnerable to numerous diseases and infestation by insects such as Leptoglossus clypealis in North America.

[33] In 2004, the rapidly growing pistachio industry in California was threatened by panicle and shoot blight first discovered in 1984.

[36] In 2022, world production of pistachios was one million tonnes (2.2 billion pounds), with the United States, Iran, and Turkey together accounting for 88% of the total (table).

Like other members of the family Anacardiaceae (which includes poison ivy, sumac, mango, and cashew), pistachios contain urushiol, an irritant that can cause allergic reactions.

[53][54] In July 2003, the United States Food and Drug Administration approved the first qualified health claim specific to consumption of seeds (including pistachios) to lower the risk of heart disease: "Scientific evidence suggests but does not prove that eating 1.5 ounces (42.5 g) per day of most nuts, such as pistachios, as part of a diet low in saturated fat and cholesterol may reduce the risk of heart disease".

[55] Although a typical serving of pistachios supplies substantial food energy (nutrition table), their consumption in normal amounts is not associated with weight gain or obesity.

[53] One review found that pistachio consumption lowered blood pressure in persons without diabetes mellitus.