As Persephone stated, M. Landon did talk of that on J. Carson's show. He made a remark, "Fill it to the rim, with Brim". Brim being a brand of coffee at the time. Not sure if that brand is even around any longer, and that sure was a funny line. Carson just looked at him, then at the audience with a straight face. But Landon had colon cancer which had metastasized to his liver, from what I recall.
On another occasion, Ernest Borgnine mentioned that he had gone to some spa and that they gave high colonics there, and said something about a yogurt enema, as I recall. Again, Carson just stared at him, then the audience, and changed the subject. I don't believe Borgnine was ever on the show again.