OK, I talked to my mother-in-law, and it was flax seed. Not the oil, just the grain. You can get it in most stores (health food section of regular grocery stores, or places like Trader Joe's or Whole Foods).

It seemed to help me when I had some difficulties with constipation. You just sprinkle a tablespoon or two on something you're eating (yogurt, whatever) several times a day. Keep it in the fridge.

Anyway, it got me past a tough spot, and I hope it might help you, too!