fwiw, this may depend on the source language (rather than -- solely? -- on org interpretation of the output block:
#+begin_src R
data.frame(a=c("this", "is", "a", "test"), b=c("tset", "a", "si", "oot,
siht"))
#+end_src
#+RESULTS:
| this | tset |
| is | a |
| a | si |
| test | oot, siht |
