stomach upset vs upset stomach

stomach upset and upset stomach both are nouns.

Word	Noun	Adjective	Verb	Adverb
stomach upset	Yes	No	No	No
upset stomach	Yes	No	No	No

As nouns, stomach upset and upset stomach are synonyms defined as:

stomach upset and upset stomach: a disorder of digestive function characterized by discomfort or heartburn or nausea

Other synonyms of stomach upset include dyspepsia, indigestion.

stomach upset (noun)	upset stomach (noun)
a disorder of digestive function characterized by discomfort or heartburn or nausea	a disorder of digestive function characterized by discomfort or heartburn or nausea