In BPH-induced rats, HCQ markedly reduced prostate weight and index, and PSA, testosterone, dihydrotestosterone, pro-inflammatory cytokines (TNF-α, κ and IL-6), and the transcription factor “NF-κB” levels, while improving histological abnormalities in epithelial and stromal tissues. This evidence concerns the gene KLK3 and benign prostatic hyperplasia.