If you have lots of debt, or if you've missed payments on your debts, this will have affected your ability to borrow more money. You might find that the only way you can borrow more money is at a higher interest rate. This means that you could end up paying more money back over the lifetime (or term) of the loan.
You may have to make a large payment to your debt consolidation loan each month, or you could find that you are paying the money back for a long period. If you're applying for any kind of loan you should always check how much the payments are each month, and how many payments you will need to make over the lifetime of the loan.