From what? A 401K or an IRA? It will add to your income and be taxable and may push you into a higher tax bracket. And if you are under 59 1/2 there is an 10% Early Withdrawal Penalty unless you have an exception. So you can lose like up to 50% with taxes and penalties. It's usually not a good idea to take a withdrawal.
if it's an employer 401k, the plan may permit loans to participants. if so, you'll have to make payments including interest and it must be repaid in 5 years otherwise any non-repaid amount becomes taxable. the advantage of a loan is that it is not taxable and there is no early withdrawal penalty. speak to your human resource department.