I'm sorry for any confusion, but "Yemen" is not a medical term and does not have a medical definition. Yemen is a country located in the southern part of the Arabian Peninsula, in Western Asia. If you have any questions related to medical conditions, symptoms, or terminology, I would be happy to help clarify those for you.
A plant genus of the family CELASTRACEAE. The leafy stems of khat are chewed by some individuals for stimulating effect. Members contain ((+)-norpseudoephedrine), cathionine, cathedulin, cathinine & cathidine.