Even at normal cabin altitudes (i.e. around 8000 ft) you can get severe abdominal pain and flatulence after eating gas forming foods or fizzy drinks. The correct counter-measure is:

Question 51, Human Performance and Limitations - ATPL - Airline Transport Pilot license

Descend to a lower altitude

Use supplemental oxygen

Perform 'valsalva manoeuvre'

Climb to a higher altitude