The TV watchdog has picked up over 1,225 complaints about three incidents, including Conor McIntyre's abusive comments about Miss India UK Deana Uppal.
Conor's explicit rant about Deana, which included a suggestion that he would "punch" her, aired on June 25 and picked up the majority of the complaints (1,108).
The Northern Irish housemate apologised to Big Brother about his comments and Channel 5 claimed that they would be taking no further action about the incident.
Other complaints were made about Caroline Wharram referring to fellow housemate Adam Kelly as a "ridiculous gorilla... with no sanitation".
Three complaints were made about former housemate Victor Ebuwa's comments on spinoff show Bit on the Side when he used the term "functioning retards" to describe the housemates.
A rep for Channel 5 said: "Channel 5 is committed to complying with Ofcom's broadcasting code and will help to facilitate a speedy investigation into this particular episode of Big Brother and Big Brother's Bit on the Side."
Channel 5's excuse for not punishing Conor at the time was that his comments were "out of character".
In a Digital Spy poll, fans overwhelmingly voted for Conor to be ejected following the incident.