The goal of this clinical trial is to learn if probiotics work to improve the response of psoriatic patients to methotrexate treatment in adults. It will also learn about the beneficial effect of probiotics on the gut microbiota of psoriatic patients treated with methotrexate. The main questions it aims to answer are: Do probiotics enhance the reduction of disease burden in psoriatic patients under methotrexate treatment? Do probiotics increase the beneficial gut bacteria and decrease the harmful gut bacteria in psoriatic patients under methotrexate treatment? Researchers will compare probiotics intake along with methotrexate to methotrexate alone to see if probiotics work to enhance the reduction of the severity of psoriasis in patients treated by methotrexate and whether the addition of probiotics will improve their gut health. Participants will: Take a daily dose of probiotics with a weekly dose of methotrexate or only a weekly dose of methotrexate for 4 months. Give daily feedback to the researchers about their probiotic intake and their dietary intake. Visit the clinic after 1 and 2 weeks of beginning treatment and then once every 4 weeks for checkups and tests.