In this study the investigators intend to compare the efficacy and safety of two fixed doses of once weekly oral methotrexate in a prospective randomized double blind manner in patients with severe plaque type psoriasis.

Inclusion Criteria:

• Patients with plaque-type psoriasis having more than 10% body surface area involvement (severe psoriasis).20
• Patients of either sex with age between 18-65 years.
• Females who were postmenopausal or tubectomised or have completed their family size and are willing to maintain contraception 1 month before, during and 1 month after completion/stopping of treatment and negative pregnancy test 2 weeks before starting of treatment and at day 2 or 3 of a normal menstrual cycle.
• Males who were willing to maintain contraception during and 3 months after completion/stopping of treatment.

Exclusion Criteria:

• Pregnant or lactating women.
• Any abnormalities in renal function, cardiovascular disease, respiratory disease or neuropsychiatric illness.
• Significant abnormalities in liver function (serum bilirubin, AST, ALT, and ALP >1.5 times the upper limit of normal), viral hepatitis or cirrhosis.
• history of excessive alcohol consumption.
• Severe anemia, leucopenia or thrombocytopenia.
• Active infectious disease or immune system deficiency including AIDS.
• history of intolerance/hypersensitivity to methotrexate.
• history of phototherapy in past 6 months.
• Patients who had received any systemic treatment for psoriasis in the past 4 weeks and topical treatment in the past 2 weeks.
• Body mass index (BMI) > 30 kg/m2.