And yes, many of our legends have appeared in low rated movies at one time or another. Douglas was fortunate to not have made many of these.
Even John Wayne really put his foot in it by making "The Conqueror" .
Just what was he thinking when he signed on to play Genghis Khan?
That film may very well have killed Wayne.
http://en.wikipedia.org/wiki/The_Conqueror_(film)#Cancer_controversy
In those days you were under contract to the studio. If they said you were going to play the third talking tree in the Magic Forest then that is what you did. You could refuse but that Studio system was an Old Boys Club and the phrase "you'll never work in this town again" was not an idle threat.