Foaming at the Mouth During Seizures: Causes & What to Expect

Foaming at the mouth does not occur in all seizures. It is most associated with generalized tonic-clonic (grand mal) seizures.

Why It Happens

• Loss of consciousness impairs swallowing and saliva control. Excess saliva pools and is forced out by jaw clenching or breathing efforts, mixing with air to form foam.
• Rapid, deep breathing (hyperventilation) during the seizure increases saliva production (sialorrhea), which cannot be managed due to impaired muscle control.

Key Points

• Foaming is brief and resolves as the seizure ends.
• Its presence or absence does not indicate seizure severity or differentiate seizure types.
• Other seizure types (absence, focal aware) rarely produce foaming.

First Aid

If someone is having a tonic-clonic seizure: protect their head, turn them on their side (recovery position) to let fluids drain, time the seizure, and call 911 if it lasts >5 minutes, they have trouble breathing, or it's their first seizure.