Tonic seizures

Tonic seizures can be generalised onset, meaning they affect both sides of the brain from the start.

Or they can be focal onset, meaning they start in just one side of the brain.

What happens during a tonic seizure?

If a tonic seizure starts in both sides of the brain, all your muscles tighten and your body goes stiff. If you’re standing, you may fall to the floor. Your neck will extend, your eyes open wide and roll upwards. Your arms may raise upwards and your legs stretch or contract. You may cry out and stop breathing during the seizure.

If a tonic seizure starts in one side of the brain, your muscles tighten in just one area of the body.


How long do tonic seizures last?

Tonic seizures usually last between three seconds and two minutes.


What happens after a tonic seizure?

Once a tonic seizure has ended, your muscles relax. You might feel sleepy or confused afterwards.


How can someone help me during a tonic seizure?

Our short online first aid course shows you what tonic seizures can look like, and how to help when someone has one. Visit tonic seizure first aid.

Download a seizure diary

Seizure diary

A seizure diary is a good way of recording information about your epilepsy.

A man being put into the recovery position

Tonic seizure first aid

Watch this short video of a tonic seizure and how to help.
Tonic seizure first aid
This information has been produced under the terms of the PIF TICK. The PIF TICK is the UK-wide Quality Mark for Health Information. Please contact if you would like a reference list for this information.
Published: July 2022
Last modified: December 2023
To be reviewed: August 2025
Tracking: A009.06 (previously B037)
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