The Bodyshockers presenter, 31, tweeted fans from her sick bed after being forced to pull out of a public appearance due to ill health.
Although Katie has not explained what exactly is wrong, she has simply told fans she is "very ill".
She posted a message on Saturday (28 March) saying: "Thanks for all your kind messages, I am back in hospital unfortunately but getting good treatment so probably the best place to be right now."
A few days before, Katie had apologised for pulling out of an event where she was due to promote her book Beautiful Ever After.
She said: "So sorry to have 2pull out of tonight, I am incredibly frustrated as I hate it when my injuries get in way of everyday life. I'm very ill.
"Just want to try and find a way forward to get back to normal health."
In 2008, Katie suffered severe burns in a horrific acid attack organised by her violent ex-boyfriend. Since then, she has undergone numerous operations and tirelessly helped fellow burns victims after launching The Katie Piper Foundation.
Earlier this March, Katie spent seven days in hospital away from daughter Belle and tweeted: "Hoping tomorrow will be discharge day from hospital for me! 7 days without my daughter - feels so cut off!"
She even missed her daughter's birthday and party because of the essential throat operation.
Thanks for all your kind messages, I am back in hospital unfortunately but getting good treatment so probably the best place to be right now— Katie Piper (@KatiePiper_) March 28, 2015
She later tweeted: "Still can't eat solids - so fiancée made me home made soup, I've got a good one."
Katie announced her engagement to Richard Sutton in December, nine months after she gave birth to their first child Belle.
She recently launched the first-ever diversity catwalk at the Ideal Home Show - and looked stunning in a black leotard.
Katie Piper: All you need to know!
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