lend me your cooking advice.

Any foodies/cooks out there I need to come up with a suitable replacement for onions in recipes. I'm allergic to onions and their various brothers (scallions, leeks etc) though it may actually be a severe intolerance as I'm not particularly allergic to other members of the lily family (or at least they don't make me anywhere near as ill) I don't really mind the absence of the textures the onions provide (all the years of digestive miseries have ingrained a dread at that familiar crunch so celery is out) I'm getting to be at a loss for what to use to replace it for flavour. Usually I just add garlic (which oddly doesn't do any damage to my innards that an acid reducer can't cure) but that's not alway a help, especially if the recipe already has garlic in it, and also I don't want to overload on garlic incase it increases my sensitivity to it (Living label scouring onion free makes buying food bad enough, a garlic free world might be nigh impossible.) Is there anything not in the lily family that would be a good substitute? (especially for leeks.)