Margo Davis is the mother of Matt Davis, the first patient in the Season 1 episode Poison. She was portrayed by actress Roxanne Hart. When Matt is rushed to hospital, Margo gets there right away and meets Robert Chase. As the team suspects that Matt may have overdosed, he asks Margo if Matt takes drugs. She insists he does not and says she used a home testing kit on Matt's hair to confirm that he was clean.