Stomachache and Inability to Eat

My mother suffers from stomachache. We went to the doctors but he do not know what the problem. The only things that she can eat is bread with jelly in the morning and soup for lunch.
If she eats something else she has to vomit. I am given her cat's claw tea and that helps but are there some other herbs that I can use?

There are many possible causes for a stomachache that doesn't allow a person to eat. It is a serious problem, and impossible to address without knowing your mother's current and past medical history.
I recommend that you visit another doctor as soon as possible. If you get no results, consult with an experienced natural health practitioner such as a medical or clinical herbalist or a naturopath.