Ethnopharmacological relevance: Thai Mucuna pruriens (L.) DC. var. pruriens (T-MP) has been traditionally used in treating depressive disorders, dysuria and enhancing male sexual desire. Although T-MP seed is demonstrated to have antioxidant capacity, its aphrodisiac and protective tissue damage properties have never been documented. Recently, ethanol (Eth) is known to cause sexual behavior dysfunction and damage reproductive system. This study aimed to investigate the protective effects of T-MP seed extract on sexual behavior dysfunction and reproductive damages in male rats admisted with Eth. Materials and methods: T-MP possessing antioxidant activity was determined for L-DOPA content using NMR analysis. Thirty-six male rats were divided into four groups (9 animals/group). Control rats received DW and the ethanol (Eth) group was given with Eth (3 g/kgBW; 40%v/v). In preventive groups (T-MP150 + Eth and MP300 + Eth groups), animals were treated with T-MP extract at a dose of 150 and 300 mg/kgBW before Eth administration for consecutive 56 days. Sexual behaviors including mounting frequency (MF), intromission frequency (IF), mounting latency (ML), intromission latency (IL), ejaculation latency (EL), post-ejaculatory interval (PEI), and ejaculation frequency (EF) were evaluated. Epididymal sperm quality and daily sperm production (DSP) were examined. Testicular histology was observed using Masson's trichrome staining. The malondialdehyde (MDA) levels and expressions of androgen receptor (AR), heat shock protein 70 (HSP70), steroidogenic acute regulatory (StAR), and tyrosine-phosphorylated (TyrPho) proteins in testis were also determined. Results: T-MP extract contained L-DOPA and improved sexual behaviors including increased MF and IF and decreased ML and IL in Eth treated rats. Significantly, sperm quality, DSP, and testicular histopathology observed in Eth group were improved after T-MP treatment. T-MP also decreased the testicular MDA levels. Additionally, T-MP could correct testicular functional proteins of AR and StAR except HSP70 expression in Eth group. Expressions of TyrPho proteins in testicular and sperm lysates were improved in co-administered groups. Conclusions: T-MP seed extract possessing L-DOPA could enhance the sexual behaviors and protect reproductive damages via improvement of testicular functional proteins.