The Partial-Oral versus Intravenous Antibiotic Treatment of Endocarditis Trial (POET) found that partial-oral outpatient treatment was non-inferior to conventional in-hospital intravenous treatment in patients with left-sided infective endocarditis. We examined the impact of treatment strategy on levels of anxiety and depression.Patients completed the Hospital Anxiety and Depression Scale (HADS) at randomization, at antibiotic completion, and after month 3 and month 6. Changes in anxiety and depression (each subdimension 0-21, high scores indicating worse) were calculated using a repeated measure analysis of covariance model with primary assessment after 6 months. Change in score of 1.7 represented a minimal clinical important difference (MCID).Among the 400 patients enrolled in the POET trial, 263 (66%) completed HADS at randomization with reassessment rates of 86-87% at the three subsequent timepoints. Patients in the partial-oral group and the intravenous group had similar improvements after 6 months in levels of anxiety (-1.8 versus -1.6, P = 0.62) and depression (-2.1 versus -1.9, P = 0.63), although patients in the partial-oral group had numerically lower levels of anxiety and depression throughout. An improvement in MCID scores after 6 months was reported by 47% versus 45% (p = 0.80) patients for anxiety and by 51% versus 54% (p = 0.70) for depression.Patients with endocarditis receiving partial-oral outpatient treatment reported similar significant improvements in anxiety and depression at 6 months, as compared to conventionally treated, but numerically lower levels throughout. These findings support the usefulness of partial-oral treatment.