It is greyish and differentiated from other grey Lactarius by its widely spaced, yellow gills.

[2] The cap is sometimes faintly concentrically banded, it is thin fleshed and becomes sticky when moist,[2] but is not shiny.

[4] The stem is between 4 and 6 cm, and between 7 and 15 mm thick, generally cylindrical but sometimes slightly swollen at the base.

[2][4] The spores are amyloid, meaning they stain dark blue in Melzer's reagent, and feature an incomplete net.

[4] Lactarius pyrogalus is fairly common[4] and is generally found at the base of hazel trees alone or in scattered groups.

[2] It is due to this taste that it received both its English name, fire-milk lactarius, and its scientific name, with "pyrogalus" translating as "fire milk".