While edible and good when cooked, it can cause gastric upset when eaten raw and can be confused with the poisonous Boletus satanas; as a result, some guidebooks recommend avoiding consumption altogether.

[27] This section traditionally included species producing medium to large fruit bodies with thick, swollen stems, and minute pores that are coloured red, orange, or rarely yellow.

[31] However, more refined analyses based on a larger number of sequences, have since demonstrated that B. luridus and its allied species form a distinct generic clade,[32] and since 2014 the fungus has been placed in genus Suillellus.

[35] Suillellus luridus is a stout fungus with a thick yellow-olive to olive-brown convex cushion-shaped cap that can reach 20 cm (8 in) in diameter.

[43][41] The flesh is yellowish, sometimes with red patches in the cap but almost always rhubarb to vinaceous-red towards the stem base, and stains an intense dark blue when bruised or cut.

[44] Variety queletiformis can be distinguished from the main form by the reddish discolouration of the stem base that occurs both on the exterior surface and in the flesh.

Cystidia on the sides of the tubes (pleurocystidia) are fuse-shaped with swollen middles and long necks, measuring 33–48 by 7.3–13.5 μm; cheilocystidia (on the edges of the pores) have a similar morphology.

The cap cuticle is made of cylindrical hyphae 3.7–5.8 μm wide that are interwoven compactly, and the hyphal tips are erect and arranged in bundles.

It produces more robust fruit bodies with a markedly tomentose cap, has a reticulum that is less pronounced and often restricted to the upper part of the stem, and is mostly found on acidic rather than calcareous soil.

[48] As shown by Vizzini and colleagues,[25] the name Boletus caucasicus has been invalidly published (nomen nudum) and the Bataille's line is not reliable for discriminating between species in the Luridi complex, as it can be randomly present or absent in both S. luridus and S. mendax.

[50] This uncommon species is also found on chalky soil under oak, but generally produces more slender and dull-coloured fruit bodies, with a rudimentary, incomplete, or at times completely absent reticulation, rarely extending below the top (apex) of the stem.

The edible Neoboletus luridiformis can be distinguished from S. luridus by its dark brown cap and absence of any reticulation on the stem; it also grows on sandy soils associated with conifers.

[36] In genus Rubroboletus, R. satanas is also found on chalky soils, but produces larger and more robust fruit bodies with a pale cap and differently patterned reticulation to S. luridus.

[51] Another red-pored species in this genus, Rubroboletus rhodoxanthus, has characteristic pinkish tones in the cap and a very dense, differently patterned reticulation.

[39] Initially collected in Michigan under oak, Boletus vinaceobasis resembles S. luridus, but has shorter spores and its cystidia are dark brown in Melzer's reagent.

[53] The Chinese species Neoboletus sinensis, originally described as a form of S. luridus but now placed in a different genus, has considerably larger spores, reported to reach 12–17 by 5.5–7 μm.

[26] Collections closely resembling S. luridus have also been recorded in Australia, though later renamed Boletus barragensis as they differ in spore size and a preference for trees of the family Myrtaceae.

[54][55] The fungus grows in a mycorrhizal association with broad-leaved trees such as oak (Quercus), birch (Betula), chestnut (Castanea) and beech (Fagus), on chalky (calcareous) soils.

[62] Several fly species have been recorded feeding on the fruit bodies, including Phaonia boleticola, P. rufipalpis, Thricops diaphanus,[63] and, in North America, Drosophila falleni, Pegomya mallochi, P. winthemi, Megaselia pygmaeoides, and Muscina assimilis.

[65] Based on phylogenetically verified collections and belowground DNA studies of mycelial distribution, the fungus appears to be native to Europe and has been so far documented in Austria, Cyprus, Denmark, Estonia, France, Italy, Montenegro and Sweden.

A number of extra-European reports can be found in literature predating DNA studies, ranging from India[72] and Pakistan,[73] to Canada,[46] the United States,[74] Mexico,[75][76] Costa Rica,[77] China[78] and Taiwan,[59] but these have not been confirmed by molecular testing and are more likely to represent similar, misidentified taxa.

[80] However, caution is advised if choosing this species for consumption, as it resembles some poisonous blue-staining boletes and some guidebooks recommend avoiding it altogether.

[4] If eaten raw or insufficiently cooked, symptoms of gastrointestinal poisoning can occur within 30 minutes to two hours, including nausea, vomiting, abdominal cramps, and diarrhoea.

Arginine is the free amino acid found in the highest concentration (96.9 μM per gram of dry weight), followed by glutamine (9.7) and alanine (8.2).

[88] The colour change observed with tissue injury is caused by variegatic and xerocomic acids, both of which turn blue when oxidized enzymatically upon exposure to air.