Christina Rossetti insisted that this was a children's poem, and it probably is, since it includes death, violent bestial assault, and potential lesbian incest.
Sisters Lizzie and Laura often hear the goblin merchant men hawking their wares, and one day Laura buys some fruit from them with her hair. After that, she begins to wither and pine, and Lizzie devises a plan to save her sister with a "hair of the dog" antidote: more goblin fruit.
Lizzie tries to buy the fruit, but the goblin men insist she eat it herself, in front of them, instead of taking it home to her sister. Lizzie tells them if she can't just take the fruit then she wants her coin back. That's when the goblins get angry:
They trod and hustled her,
Elbowed and jostled her,
Clawed with their nails,
Barking, mewing, hissing, mocking,
Tore her gown and soiled her stocking,
Twitched her hair out by the roots,
Stamped upon her tender feet,
Held her hands and squeezed their fruits
Against her mouth to make her eat.
After this horrific attempted-oral-fruit-rape, Lizzie returns to Laura triumphant and asks her to lick and suck all the fruit juices off her body. When Laura does, she is miraculously healed. The moral, the story tells us, is "there is no friend like a sister." This is what best convinces me that it is in fact a children's poem. Parents can defuse a sibling fight by saying, "Be nice to your sister; she would cover herself in fruit juice for you and let you lick it off, so you need to let her have a turn playing with the Barbie corvette now."
Fruit is very, very bad for you.
Rossetti, Christina. "Goblin Market." Goblin Market and Other Poems. London: Macmillan, 1865. 1-30.