I Am Taking Care Of My 79 Yr Old Aunt

I am taking care of my 79 yr old aunt who is mentally handicapped - and she doesn't express problems well. Early this morning she woke up vomiting -and has dirtied her pants once and has gone a few times but she doesn't seem to have a lot of diarrhea. She has vomited 5-6 times which is weird because she has nothing in her - it has been very smelly and yellow. It doesn't seem like the flu or a cold since she has no fever or any other symptom. Could this be a virus that needs to pass and should I give her something for vomiting?