Hypericum hircinum is a species of perennial flowering plant in the St John's wort family, Hypericaceae.

It is known as goat St John's wort and stinking tutsan; both names refer to the plant's distinctive odor.

The species is a bushy shrub that can grow up to 1.5 meters tall, is many-stemmed, and has golden yellow flowers with conspicuous stamens.

At one point the plant was placed into the defunct genus Androsaemum, but it was returned to Hypericum by Norman Robson in 1985.

The species is highly variable in appearance, but its lack of geographic separation means that five subspecies have been established to account for its diversity.

Extracts from the species contain the highest levels of chemicals when taken from the flowering structures during the fruiting period of the plant.

Modern evaluations have demonstrated the plant's effectiveness as an antioxidant, anti-collagenase (for cosmetic care), and antimicrobial agent.

The stamens are bundled together in groups of around twenty, the longest of which are 1.2–2.2 cm long; this is conspicuously longer than the petals.

The plant today known as Hypericum hircinum was well-studied and documented before the modern system of botanical nomenclature was established.

For example, the plant may have been mentioned under the name "Ascyroides" as early as 1627 in Prospero Alpini's De plantis exoticis.

In the codex, the plant was noted to be from Sicily, of the grouping Hÿpericon (an early version of Hypericum), and called "Androsaemum foeditum" or "Tragôdes".

Triadenioides H. canariense H. bupleuroides H. androsaemum H. hircinum H. foliosum H. grandifolium The species was brought back to Hypericum by Norman Robson in his monograph of the genus.

[12] A 2013 study used Bayesian inference to establish the phylogeny and close relations of Hypericum species.

[11] The genus name Hypericum is possibly derived from the Greek words hyper (above) and eikon (picture), in reference to the tradition of hanging the plant over religious icons in the home.

[14] Another term used by early botanists to name the species was "foetidum", which comes from the Latin word "foetĭdus" and means a foul or fetid odor.

[18] In addition to his specific description of Hypericum hircinum, Norman Robson also streamlined its infraspecific organization.

Because of the species' high variability in appearance but lack of geographic discontinuity, Robson acknowledged that there are at least five subspecies of H.

[22] Carl Linnaeus noted the presence of Hypericum hircinum in Sicily, Calabria, and Crete in the 18th century;[9] Édouard Spach stated in 1836 that it was found in "southern Europe and the East".

[10] Today, the species is recorded as native in Saudi Arabia, Jordan, Syria, Cyprus, Turkey, Greece, Italy, France, Spain, and Morocco.

The species is highly prone to escaping from this cultivation, and has become integrated into the native ecosystems of numerous areas, especially in Spain, France, and Sicily.

The plant is also used topically, with its oil applied to skin burns and its extracts used to relieve rheumatism and other muscular ailments.

It has greater antioxidant capabilities than the well-studied Camellia sinensis, due largely to the presence of flavonols, flavanones, and caffeoylquinic acids.