Doctor of Philosophy / Department of Horticulture, Forestry, and Recreation Resources / Richard H. Mattson / Medical and psychological responses of patients recovering from surgery were evaluated in hospital rooms with ornamental indoor plants. Three clinical studies were conducted in two hospitals with 80 thyroidectomy patients, 90 appendectomy patients, and 90 hemorrhoidectomy patients. Patients in each surgical procedure were randomly assigned to either control or plant rooms. Eight species of foliage and flowering plants were placed in the hospital rooms during the recovery period following surgery until discharge. Data collected from each patient included length of hospitalization, analgesics used for postoperative pain control, vital signs (blood pressure, temperature, heart rate, and respiratory rate), ratings of pain intensity, pain distress, anxiety and fatigue (PPAF), the State-Trait Anxiety Inventory Form Y-1 (STAI-Y1), the Environmental Assessment Scale (EAS), and the Patient’s Room Satisfaction Questionnaire (PRSQ). Effects were assessed by analysis of covariance and the exact chi-square test. Patients in the plant rooms had significantly more positive health outcomes than those in the control group with no plants. Patients exposed to plants experienced shorter hospitalizations, fewer intakes of postoperative analgesics, more positive physiological responses, and less pain, anxiety, and fatigue than patients in the control group. Patients with plants also felt more positively about their rooms and evaluated them with higher satisfaction as compared to those in the control group. Based on patients’ comments, plants brightened up the room environment, reduced stress, and also conveyed positive messages of the hospital caring for patients. Findings of this study confirmed the therapeutic value of plants in the hospital environment as a noninvasive, inexpensive, and effective intervention for surgical patients in a general hospital ward. Outcomes of this study will substantially affect patients’ and hospital administrators’ decisions that indoor plant intervention can foster improved medical outcomes, increase satisfaction with providers, and be acceptably cost effective as compared to other alternatives.