Fly in the ointment

Meaning

A small snag that spoils an otherwise good situation.

Usage

Used when warning to watch for minor but critical issues.

Origin & History

Origins and dates here are approximate summaries. Many idioms have disputed or unknown origins, and not every date has been checked against a historical dictionary, so treat specific dates and stories as a starting point rather than a citation.

Old remedy stories noted insects in ointments ruined them.

Bible-based imagery that survived into general parlance.