Objective: To Determine The Periodontal Therapy Effects On Female Psychiatric Patients From Hospital Mental Nuestra Senora Del Perpetuo Socorro, Pasto, Colombia In 2008. Methods: Thirty Six Persons With Periodontal Disease Were Enrolled In This Crossover Study With Committee Ethical Approval. 18 Female Psychiatric Patients Were Assigned To Cohort 1 And 18 Female With Mental Health To Cohorte 2. The Assessed Parameters Were Quigley-Hein Modified By Turesky Oral Hygiene Index, And Sulcus Bleeding Index. Other Clinical Features Such As Clinical Attachment Level And Probing Depth Were Measured At Baseline And 1, 3 Months. Results: The Periodontal Therapy Resulted In Overall Improvement In All Clinical Parameters In Both Group At 3 Month. In The Cohort 1, There Was A Mean CAL Gain Of 0.6 Mm And Mean PD Reduction Of 0.9 Mm Both Were Statistically Significant (p<0.05). In The Cohort 2 Group, There Was A Mean CAL Gain Of 0.7 Mm And Mean PPD Reduction Of 0.9 Mm Both Were Statistically Significant (p<0.05), As Well. Conclusions: Even Though The Psychiatric Patients Had A More Severe Periodontal Disease, The Periodontal Changes Were Similar To The Cohort 2 Group After Periodontal Therapy.