Police said a woman with mental health issues, who was living in Sidmouth, had to be tasered when she pulled a seven-inch knife on an officer.
The woman, said police, had been receiving regular welfare visits by PCSOs, but she became hostile when officers saw her last Friday afternoon.
They were accompanying mental health officers looking to return her to her Yorkshire home when she brandished the weapon.
Police said she was tasered twice for her own safety and that of the officers.
The woman was handcuffed and taken by ambulance to the Royal Devon and Exeter hospital.
She was transferred to a mental health facility and has now been sectioned, said police.
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