Blood and vometing

Question
Hello. I have a chihuahua, who is about seven y.o. The problem she has sometimes is vomiting some bright yellow stuff, upset stomach, as well as little bit of blood in her stool,and her stool is like a jello. She has it rearly, but at least once a month. She does NOT appear suffering of any kind,as she will always play, and her apetite is good. It got to the point, when one time she had the same stool, and i picked it up with a plastic bag, took it to the vet,so they can sand it to the lab. And they did. The result came negative of any deseases. So I was wondering what can be wrong? Sincerely, Armen.

Answer
Hello,
Most dogs will go out and eat grass if they have a queasy stomach.  I have six dogs and they all throw up yellow once in awhile or have a loose stool.   However, I have seen this happen to dogs that have tape worm.  It looks like little rice grains around the anus and comes from eating a flea.  Also, roundworms can cause stomach upset.  I have even had dogs throw up a roundworm.  Make sure she doesn't have worms, or isn't eating anything she shouldn't.  She should be able to eat grass if she needs too, it will make her throw up anything that is upsetting her stomach.
Not to worry.
Nancy
PS  make sure she is not getting any ibeprofen or naproxen, that will make her stomach bleed.