The present study will be conducted on fifty participants. All participants will receive a full-mouth clinical examination, and the following periodontal parameters will be recorded: Plaque Index (PI). Gingival Index (GI), probing depth (PD), and clinical attachment level (CAL). All of these measurements will be recorded at six sites at baseline for all participants and 3 months after non-surgical periodontal therapy for the study group. GCF samples will be collected from the buccal aspects of teeth that had the highest signs of inflammation and attachment loss for periodontitis group at baseline and 3 months after non-surgical periodontal therapy. As for controls, the samples will be collected from buccal aspect of upper first molar at baseline. The samples will be assayed for prolactin by using an enzyme linked immunosorbent assay kits (Elisa) according to the manufacturer instruction.

Inclusion Criteria:

• Subjects with moderate to severe chronic periodontitis, with probing pocket depth (PPD) ≥ 4-6 mm and clinical attachment level ≥ 4-5 mm, according to the American Academy of Periodontology.7
• Highly motivated and cooperative patients

Exclusion Criteria:

• The presence of any systemic disease.
• Taking medications for the last 3 months before conducting this study.
• Pregnancy and lactation.
• Any type of previous periodontal treatment (surgical or non-surgical) in the preceding 6 months.
• Smoking (former or current).