Suggest Over The Counter Medication To Treat Abdominal Distension

Question: My family has a history of Upper GI distension, and highly allergic for which cholecystectomy has NOT helped. I have recently suffered from it. I am not taking probiotics as they produce allergic symptoms. Endoscopies have been negative. the symptoms have worsened after Hurricane XXXXXXX (as have many in the city of Houston), The air in the city is highly contaminated with a variety of allergens - mold, decaying housing and structures/wood/etc. much of which is still on the streets. I left town for a week for cold weather, and was much better, but since return the symptoms have also returned. I figure it is related to an allergic reaction with cholinergic symptoms. In the past my father (who is now deceased) used Donnagel - I know it is now a scheduled drug and no longer available , Gas X works to a certain extent, but temporary. IS there some over the counter or natural fix for this - that would provide symptomatic relief without a prescription? (I am a nurse with several additional credentials - with 30 yrs of experience. )
If you could recommend something I would be grateful.