‘If you lie down with dogs, you will get up with fleas’ is an early English proverb. It dates from the 16th century – a time when a close acquaintance with fleas was a more familiar experience than it is now.
The expression is first found in print in the English writer James J. Sanforde’s Garden of Pleasure, 1573. The book was intended as a collection of proverbs and witty sayings. Sanforde described it as being “Done out of Italian into English”, that is, translated, and its secondary purpose was to aid speakers of one language learn the other.
He that goeth to bedde wyth Dogges, aryseth with fleas.
See also: the List of Proverbs.