Legal analysis: If the signature is cheated and there is no real loan relationship between the two parties, the IOU is invalid. It must be proved that the IOUs were signed by cheating. If there is no evidence, it is generally considered effective. IOUs are different from general contracts. Only the signature is illegal, and the content and signature must be written by the debtor. At the same time, you can accuse the other party of fraud.

Legal Basis: Some Issues on the Application of Law in the Trial of Private Lending Cases in the Supreme People's Court Article 21 The people's court shall not support the loan certificate or the loan contract signed or sealed by others, such as IOUs, receipts, IOUs, etc., but they do not indicate that they are the guarantor or assume the guarantee responsibility, or they cannot be presumed to be the guarantor through other facts.