Entecavir, when taken by men, generally has no significant effect on fertility, and toxicity testing, safety, and side effects have not suggested that the drug affects fertility. 1. Toxicity testing: Entecavir was tested for genotoxicity and reproductive toxicity prior to marketing, and the results were negative. 2. Safety: Entecavir is an antiviral drug with a safety class C. It is commonly used in clinical practice, and there are no reports of reproductive effects. 3. Toxic side effects: The drug insert for entecavir contains no adverse effects on fertility, suggesting that no adverse effects have occurred during previous use. Common adverse reactions to entecavir include nausea, myalgia, rash, dizziness, fatigue, and abdominal pain; entecavir is contraindicated in people who are allergic to it. Entecavir carries certain risks, and patients need to be guided by a specialist and should not take it without authorization.