I too suffer from Ulcerative Colitis, but luckily haven't had a flare up for a long time (touching wood, as I write this!). I've rarely had the constipation, but I know how terrible it is when it happens. I never knew that straining could trigger a heart attack, but I'm not surprised.
chattylady, I'm glad you've found something that works for you. I used to take aloe vera, but a naturopath suggested I try ground flax seeds and flax oil for regularity, and I find it really works for me. I put them both in a blueberry/soy milk soothie, every morning...delicious! I highly recommend the combination for "smooth" bowels
Wishing good health to all,