excretion vs excreta

excretion and excreta both are nouns.

Word	Noun	Adjective	Verb	Adverb
excretion	Yes	No	No	No
excreta	Yes	No	No	No

As nouns, excretion and excreta are synonyms defined as:

excretion and excreta: waste matter (as urine or sweat but especially feces) discharged from the body

Other synonyms of excretion include body waste, excrement, excretory product.

excretion (noun)	excreta (noun)
the bodily process of discharging waste matter	waste matter (as urine or sweat but especially feces) discharged from the body
waste matter (as urine or sweat but especially feces) discharged from the body