Why?
Plain marshmallows are mostly sugar and gelatin — not poisonous, but no nutrition either. The real danger is sugar-free marshmallows sweetened with xylitol.
⚠️ Watch out for
Sugar upset; xylitol versions cause collapse and seizures.
✅ Safe way
One plain marshmallow isn't an emergency. Always check for xylitol first — if present, vet immediately.