Thank you for your query,
In children vomiting
follows the cough
and it is called posttussive vomiting.
The cough may be allergic or a viral throat infection
For cough you can give cough syrup which can be available over the counter for some relief.
Once the cough gets controlled the vomiting will subside auomatically.
No medication is required for vomitings.
But consult your Pediatrician
for her throat and lungs examination to prescribe her a specific cough medicine.
Hope I have answered your query.