The bad kind of gas is a result of a very sour intestinal track that firments the foods consumed into making a deadly gas that bloats the person and makes them very ill. It is the same type of gas that results in the common cowq barn lot of manure and can be converted into a fuel that can power an enjine.
It takes years of wrong living to create such an environment to creat such gas.
More common gas comes from mixing wrong foods which leads to firmentation.
Some doctors have written that the common adult thart eats grains/milks, etc. creates more alcohol in their intestines than the town drunk drinks...this would be the result of firmentation aka gas in my opinion. The cure is always the same, one cure for all, correct the diet and stop the daily poisons.