That side effect would come in handy, if you have need of a cough medicine, and have recently partaken in Taco Bells daily special.
When I were a lad, me Mam had a small bottle of laudanum to relieve "the trots". For a long time I could never fathom the connection with the communists. Grandad was always banging on about "those bloody Trots"! Then it occurred to me they gave him the shits :-)