Former Environment Secretary Therese Coffey said she "nearly died" because of the stress of being a government minister.
Ms Coffey, the Conservative MP for Suffolk Coastal, revealed how tough she found being a minister in a BBC radio interview.
The MP resigned from her job as Prime Minister Rishi Sunak reshuffled his cabinet.
She said: "Nearly five years ago I got so ill, I nearly, dare I say it, died."
Ms Coffey, who said she was proud to have served under five Conservative leaders, resigned as environment secretary as Prime Minister Rishi Sunak reshuffled his ministers.
Her previous cabinet roles included two months as both secretary of state for health and social care and deputy prime minister under Liz Truss.
During a frank interview, Ms Coffey told BBC Radio Suffolk: "I was in hospital for a month with some of the stresses that happen with ministerial life.
"A few years ago I certainly worked myself into the ground somewhat, but I learned a lot from that incident and that's why I've always had a joy about life."
Meanwhile, the founder of a group trying to clean up Suffolk's River Deben said she was "delighted" Ms Coffey was no longer environment secretary and hoped she would spend more time supporting the river campaign.
Ruth Leach, from Save the Deben, said she hoped the resignation would end conflicts between her constituency and ministerial duties.
Rachel Smith-Lyte, East Suffolk Council's cabinet member for the environment, a member of the Green Party, added: "I'm amazed she's been around as long as she has, both in terms of being environment minister, which is laughable, and as an MP for this area."
Ms Coffey told BBC Radio Suffolk she was proud of her record as environment secretary.