Dr. Mary Guo treats patients for a variety of skin conditions, including atopic dermatitis, psoriasis, vulvar rash, skin cancer, acne/rosacea, and vesiculobullous disease. She offers an excision clinic for benign and malignant skin neoplasms, and she operates the SLUCare Women's Health and Genital Dermatology Clinic.

She is interested in research into vulvar rash and quality improvement in patient care.

Dr. Guo is an associate professor in the Department of Dermatology, Division of General Dermatology, at Saint Louis University School of Medicine.

She is a member of the American Academy of Dermatology, the American Medical Association, and the Women's Dermatology Society.

Prior to becoming a physician, Dr. Guo was a midwife and registered nurse. In her spare time, she plays competitive badminton.