Objective: To investigate the clinical effect of orally taken Huoluo decoction with external using Dingxiang ointment in the treatment of postherpetic neuralgia (PHN) and its mechanism of action. Method: One hundred-ten patients were randomly divided into observation group (n=55) and control group(n=55). Both groups were given acupuncture treatment

the course of treatment was 10 days. The control group was given Vitamin B1 tablet orally

50 mg/time

3 times/day

methylcobalamin

0.5 mg/time

3 times/day

diclofenac sodium dual release enteric-coated capsules

75 mg/time

1 times/day. Taking paracetamol and tramadol hydrochloride tablets orally when it is necessary. The course of treatment was 8 weeks. The observation group was given oral Huoluo decoction

and external using Dingxiang ointment

treatment course 8 weeks. Pain relief degree by VAS

and calculate the pain decline index;record of quality of life (QOL) score before and after the treatment.Record the dosage in group of acetaminophen tramadol during the treatment.Test the level of T cell subsets and serum interleukin 6 (IL-6) and interleukin 2 (IL-2) before and after treatment. Result: The total effective rate of observation group on pain reduction index (95.54%) were lower than the control group (78.18%) (P< 0.05);the both groups using the VAS score were significantly decreased.The VAS scores of observation group were lower than the control group at the second

fourth and eighth week after treatment(P<0.05 or P<0.01);the level of CD3

CD4 and CD4/CD8 in observation group of was superior to the control group

the level of CD8was lower than the control group(P<0.05 or P<0.01); the level of IL-6 in the two groups were reduced(P<0.01)

while the observation group was lower than control group (P<0.01);The level of IL-2 in the two groups were rising(P<0.01); while the observation group was higher than control group (P<0.01);the QOL scores of observation group was superior to the control group;the dosage in group of acetaminophen tramadol of observation group was less than the control group(P<0.01). Conclusion: Using the Huoluo decoction taken orally with Dingxiang ointment can quickly reduce the relieve PHN pain symptoms and the dosage in group of acetaminophen tramadol

which improve the patients' life quality. The mechanism may be related to regulate immune function

reduce inflammation injury and promote the recovery of neural function.