Acyclovir tablets have few side effects, common side effects can be manifested as digestive symptoms, allergic reactions, neurological changes, blood system reactions and other manifestations, due to individual differences, the side effects manifested by each person are different. 1. Gastrointestinal symptoms: nausea, vomiting, diarrhea, constipation and other symptoms are common. 2. Allergic reactions: Itchy skin, rashes and even acne may occur. 3. Neurological changes:Headache, dizziness, blurred consciousness, confusion, etc. may occur. 4. Hematological reactions:A few patients may experience thrombocytopenia, anemia, and leukopenia. The drug should be used with caution in pregnant and lactating women, and is contraindicated in those who are allergic to the drug. If you need to use acyclovir tablets, it is recommended to go to a regular medical institution to consult a physician after use, do not self-medication.