The Collaborative International Dictionary of English v.0.48:

Excreta \Ex*cre"ta\, n. pl. [L.]
   Matters to be excreted.
   [1913 Webster]

WordNet (r) 3.0 (2006):

excreta
    n 1: waste matter (as urine or sweat but especially feces)
         discharged from the body [syn: body waste, excretion,
         excreta, excrement, excretory product]