The purpose of this study is to evaluate the efficacy and safety of Foscarnet Sodium and Sodium Chloride Injection in patients with herpes zoster, and observe incidence of Postherpetic neuralgia

Inclusion Criteria:

1.Patients with clinical diagnosis of Herpes Zoster, and able to be enrolled into the study ≤ 72 hours from appearance of rash; 2.18-65 years old, men and women; 3.VAS score≥4; 4.Patients haven't receive any antiviral medication before enrollment; 5.Patients able to understand the study procedures, agree to participate and give written consent.

Exclusion Criteria:

1. Patients with history of allergy to Foscarnet Sodium or Acyclovir;
2. Other combined infection (bacteria, fungi)
3. Severe decline in immune function, or long-term use of corticosteroid and immunosuppressor
4. Serious liver or renal function abnormalities (Aspartate Transaminase(AST) or alanine transaminase(ALT) ≥ 2.5x upper limits of normal(ULN), Creatinine(Cr) or Blood urea nitrogen(BUN)≥ 1x ULN)
5. Women who are pregnant or lactating, and women of childbearing potential failed to use an adequate method of contraception to avoid pregnancy;
6. Patients using other antiviral drugs;
7. Long-term use of non-steroid anti-inflammatory drug, tricyclic antidepressant, anti-epileptic drugs or analgesic
8. Current malignant tumor;
9. Patients investigators consider as inappropriate to participate in the study