From the Manual of the Game:
Alandra is respected for her skills with medicines. Her herbal tinctures can heal bad wounds, and she is so proficient in the art of healing that she can mend broken legs. In a crisis, she does not hesitate to draw her sword and take whatever action is necessary.
Passive skill: The collection after each sermon in the Cathedral is larger.
Active skill: Alandra can cure sick settlers who are near her.