I really feel for you, I have the same problem only I have 'rotten egg' smelly burps too, like you it only happens in the evening after my meal. My doctor doesnt seem to know whats going on and has given me colpermin (peppermint oil) for IBS, I know I havent got IBS as I have no pain, constipation or diarrhoea. If you find out whats going on........please let me know, this is so embarrasing.
I am having the exact same problem. I have bad flatulence that smells terrible every night but not during the day. On occasion I don't have bad wind, it seems to vary but I can find no pattern in it in terms of diet. I have tried not eating dairy and it made no difference, I am under the suspicion that alcohol or garlic could make it worse but I can't tell because sometimes it happens when I haven't consumed those foods.
I have seen the doctor and they say I have IBS but my main symptom is bad gas. I don't have bad bowel movements, really. Just horrible burning gas. My boyfriend can hardly stand it, I feel so bad. It is so embarrassing.
I was taking peppermint oil pills but I couldn't tell if those made a difference. I stopped because the bad gas stopped for a while. But now it is back.
Have either of you found any remedies to this terrible problem?