Diane Abbott has said the condition that caused her to take a break from election campaigning was type 2 diabetes.
She told The Guardian that she was first diagnosed with diabetes two years ago, but during the election campaign her condition was out of control.
The shadow home secretary has now claimed that she is managing the condition and is ready to work again, according to the BBC.
Type 2 diabetes can be controlled with medication and changing diet and lifestyle habits.
During the general election campaign Abbott seemed to struggle during interviews and couldn't give exact figures in response to questions.
The MP also dropped out of an interview with BBC's Woman's Hour at short notice and many reports claimed Labour had lost confidence in her abilities.
Then the day before the election (June 7), Abbott was replaced as shadow home secretary by Lyn Brown as she took sick leave.
Abbott claims that she hadn't eaten enough food when appearing publicly in the election campaign and that had affected her blood sugar levels.
She said: "During the election campaign, everything went crazy, and the diabetes was out of control, the blood sugar was out of control."
Prime Minister Theresa May also suffers from diabetes, although she has type 1.