I do not think she ingested sometjing toxic. Something irriating is much more likely. She has been trying to bring the offisive item up and what you were witnessing sounds like a reverse sneeze. It is very much like a hiccup. You can read about it here:
When your baby gets home give her some bread and butter and cottage cheese in addition to her food. This spongy material will help her push out leaves, grass, etc so she should feel much better.
Please let me know how she is and if you have ore questions. I am happy to help in any way possible.