The English idiom “to make a mountain out of a molehill” is not often used in day-to-day exchanges but is a commonly found metaphor in newspaper articles and in literature. It is not only a metaphorical expression but is also alliterative and this is what causes it to be used often in both literature and poetry.
The expression is used to suggest that someone has over-reacted to a generally minor issue. This issue is normally something negative rather than the over-reaction to for example a surprise gift. IT might be used when someone is angry about something fairly banal which will not have a big impact upon their life.
The expression can be dated back to the 16th century. The first recorded use was in 1548 in a translation of The first tome or volume of the Paraphrase of Erasmus vpon the newe testamente by Nicholas Udall. He wrote in this translation, “The Sophistes of Grece coulde through their copiousness make an Elephant of a flye, and a mountaine of a mollehill.” Over time the spellings of several of the words have changed; for example “mountain” and “molehill,” but the expression has remained the same and has the same meaning. It is suggested that it was when Thomas Bacon used the expression in 1563 in Catechism that it gained popularity and was cemented into the English language.
An example of this expression can be found in the title of an article on the BBC news website from October 2014 which focuses on the underground economy. It reads, “Black money: Making a mountain out of a molehill?”