The Collaborative International Dictionary of English v.0.48:

Eupeptic \Eu*pep"tic\, a. [Gr. ?.]
   Of or pertaining to good digestion; easy of digestion; having
   a good digestion; as, eupeptic food; an eupeptic man.
   [1913 Webster]

         Wrapt in lazy eupeptic fat.              --Carlyle.
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

88 Moby Thesaurus words for "eupeptic":
   accepting, alive and kicking, at ease, beaming, blithe, blithesome,
   bright, bright and sunny, bright-eyed and bushy-tailed, charmed,
   cheerful, cheery, chipper, comfortable, composed, content,
   contented, cozy, delighted, easy, easygoing, elated,
   enjoying health, euphoric, exalted, exhilarated,
   favorably impressed with, fine, fit, fit and fine, flushed,
   full of beans, genial, glad, gladsome, glowing, gratified, happy,
   healthful, healthy, high, hopeful, in clover, in condition,
   in fine fettle, in fine whack, in good case, in good health,
   in good shape, in good spirits, in health, in high feather,
   in high spirits, in mint condition, in shape, in the pink,
   intrigued, irrepressible, laughing, of good cheer, of good comfort,
   optimistic, pleasant, pleased, pleased as Punch, pleased with,
   radiant, reconciled, resigned, riant, rosy, sanguine, sanguineous,
   sans souci, satisfied, smiling, sold on, sparkling, sunny,
   taken with, thrilled, tickled, tickled pink, tickled to death,
   uncomplaining, unrepining, winsome, without care