Lactarius xanthogalactus, commonly known as the yellow-staining milkcap is a poisonous species of fungus in the family Russulaceae. It produces mushrooms with pinkish-cinnamon caps up to 11 cm (4.3 in) wide held by pinkish-white stems up to 6 cm (2.4 in) long. When it is cut or injured, the mushroom oozes a white latex that rapidly turns bright sulfur-yellow. The species is found on the west coast of the United States and grows in the ground in association with hardwood and conifer trees. There are several other Lactarius species that bear resemblance to L. xanthogalactus, but most can be distinguished by differences in staining reactions, macroscopic characteristics, or habitat.