Written IOUs have legal effect. Under normal circumstances, IOUs should be signed and sealed, because the law stipulates that if the parties conclude a contract in the form of a contract, they should sign or seal it. The people's court shall consider that the fingerprints of the parties on the contract have the same legal effect as the signatures or seals.

The contents of the IOU are as follows:

1. Clearly stipulate the legal full names of the borrower and the lender;

2 loan amount should be clearly agreed, including the amount expressed in words and figures;

3. The loan term should be clearly agreed, including the start and end date of the loan and a clear loan term;

4. Clearly stipulate the specific repayment date;

5. There must be a clear agreement on the interest of the loan, and there must be a clear annual interest rate or monthly interest rate, as well as the total loan interest that should be paid in the end;

6. Clearly stipulate the date, month, day, time and payment method for repayment of loan principal and interest;

7. The borrower shall personally sign, hand print or hand-written signature.

Can you sue just because of an IOU?

You can sue by virtue of this article.

If the creditor fails to claim the arrears, he can bring his identity card, complaint, etc. Bring a civil lawsuit to the court. Even if there is only one iou, you can sue, as long as you meet the conditions for prosecution, you can sue, and you don't have to have evidence. However, in the trial stage after the prosecution, if there is not enough evidence to prove the existence of the loan relationship, it is likely to lose.

Prosecution must meet the following conditions:

1. The plaintiff is a citizen, legal person and other organization that has a direct interest in this case;

2. There is a clear defendant;

3, there are specific claims and facts and reasons;

4. It belongs to the scope and jurisdiction of the people's court to accept civil litigation.

To sum up, IOUs have legal effect. As long as the reason and amount of arrears are clearly written and signed by the debtor, the IOU has legal effect.

Legal basis:

Article 143 of the Civil Code of People's Republic of China (PRC)

A civil juristic act that meets the following conditions is valid:

(1) The actor has corresponding capacity for civil conduct;

(2) the meaning is true;

(three) does not violate the mandatory provisions of laws and administrative regulations, and does not violate public order and good customs.