Legal analysis: You can sue as a creditor if you borrow money and fail to repay it, but the IOU is one of the evidences of the creditor's rights and debts. If there is no IOU, the probability of winning the lawsuit may not be high, but other evidence can be collected to prove both parties There is a creditor-debt relationship, and the intervention of a professional lawyer can help the parties recover their debts better.

Legal basis: "Civil Procedure Law of the People's Republic of China"

Article 63 evidence includes: (1) Statements of the parties; (2) Documentary evidence; ( 3) Physical evidence; (4) Audio-visual materials; (5) Electronic data; (6) Witness testimony; (7) Appraisal opinions; (8) Inspection records. Evidence must be verified to be true before it can be used as a basis for determining facts.

Article 119: A lawsuit must meet the following conditions: (1) The plaintiff is a citizen, legal person or other organization that has a direct interest in the case; (2) There is a clear defendant; (3) There are specific litigation claims, facts and reasons; (4) It falls within the scope of the people's court to accept civil litigation and the jurisdiction of the people's court subject to the lawsuit.