Noun
The act of belching wind from the stomach; a belch.
A violent belching out or emitting, as of gaseous or other matter from the crater of a volcano, geyser, etc.
Source: Webster's dictionaryAlthough the article doesn't specify whether the methane is released by flatulence or eructation, it appears the headline-writer assumes it's through flatulence. Source: Internet
Secondly, studies aiming to quantify the total volume of gas produced by IBS patients (some including gas emitted from the mouth by eructation) have consistently failed to demonstrate increased volumes compared to healthy subjects. Source: Internet
This is emitted from the mouth by eructation (burping) and is normal. Source: Internet