take the bull by the horns

take the bull by the horns  {v. phr.},  {informal}

To take definite action and not care about risks; act bravely in a difficulty.

He decided to take the bull by the horns and demand a raise in salary even though it might cost him his job.

Compare:

TAKE THE BIT IN ONE'S MOUTH,

TAKE THE LAW INTO ONE'S OWN HANDS.