Allemand was discovered by her boyfriend, NBA player Ryan Anderson, She was rushed to University Hospital.
The family said was taken off life support Wednesday and she died "peacefully with her mother, boyfriend and other lifelong friends by her side."
Gia Allemand appeared on Season 14 of ABC's reality dating competition "The Bachelor," which aired in 2010, opposite commercial airline pilot Jake Pavelka. She went on to compete on the first two seasons of the spinoff show "Bachelor Pad."
"Loved ones and fans will remember Gia Allemand as a caring woman who loved her family and was well-known for her compassion towards animals and mission to rescue homeless pets," the family statement said.
Host Chris Harrison tweeted: "It's with heavy hearts that we say goodbye to our good friend Gia Allemand. She will be loved and missed by all who knew her."
Former "Bachelor" Pavelka said he was "devastated" over the news, calling her "a very dear friend."
"We have lost (an) angel today. I miss you Gia," he tweeted.