Objective       To investigate the protective effect of L-carnitine on the sperm DNA damage in the patients with male infertility.       Methods       Eighty-eight infertile men with abnormal sperm DNA integrity [DNA fragmentation index (DFI)15%

]

admitted in Jinling Hospital from September 2012 to April 2014 were recaited in t

his study

and then randomly divided into a treatment group (44 patients) treated orally with L-carnitine (1 g

tid) and a control group (44 patients) treated with Wuziyanzong bolus (6 g

bid)

both for 3 months. Semen parameters were measured by computer assisted semen analysis (CASA) and sperm DFI was detected by flow cytometry before and after treatment.       Results       There were no significant differences in the DFI

sperm concentration

percentage of total sperm motility and progressive motility between the 2 groups before treatment (P0.05). After treatment for 3 months

remarkable improvement was observed in the percentage of total sperm motility in the treatment group [(47.28±17.65)%

]

compared with the control group [(33.82±14.33)%

]

and before treatment [(25.45±15.36)%

P0.01

]

. The progressive motility was higher in the treatment group [(35.13±13.24)%

]

than in the control group [(25.42±11.34)%

]

and before treatment [(19.87±10.88)%

P0.01

]

. The treatment group [(30.74±15.51)×10

6

/mL

]

showed significant increase in the sperm concentration compared with the control group [(24.46±15.36)×10

6

/mL

]

and before treatment [(22.60±18.39)×10

6

/mL

P0.05

]

. The sperm DFI was significantly decreased in the treatment group [(13.57±5.89)%

]

compared with the control group [(20.34±5.28)%

]

and before treatment [(23.83±6.32)%

P0.05

]

. After treatment

the above parameters had no significant changes in the control group (P0.05).       Conclusion      L-carnitine may effectively improve the sperm motility and sperm DNA integrity in the patients with male infertility.