Laura Smith was a clinic patient in the Season 3 episode Lines in the Sand. She was portrayed by actress Kat Sawyer-Young (credited as "Kat Sawyer").
Gregory House was hanging out in the clinic because of a dispute with Lisa Cuddy over the carpet in his office. unfortunately, the clinic patients were even more boring than usual. Laura suffered from chronic constipation. She had just had one of her rare bowel movements, but the stool was so misshapen that she was worried, so she wrapped it up and brought it to the hospital for a doctor to look at.