The victim was asked by one of female friend to accompany her after the latter was invited by a male friend to his house in Vakola last evening, they said.
As the victim reached there, four boys were already present in the house.
After the six had a friendly chat, the boys started consuming alcohol. After a while, the victim was given spiked drinks following which she lost conscious.
The boys then raped her, police said. The accused, including the victim's female friend, are absconding, they said, adding that alcohol bottles were also recovered from the house.
The victim was rushed to civic run V N Desai hospital where she is undergoing treatment, police said, adding a case was registered and manhunt was launched for the accused.