Endometritis and postpartum dysgalactiae syndrome are common postpartum disorders in sows revealing antimicrobial treatment. This study evaluated the influence of the intrauterine application of a phytotherapeutic agent (EucaComp©) after farrowing containing essences of marjoram, marigold, melissa and eucalyptus and other sow-related parameters on the uterine involution. In total, 150 Landrace x Large white sows (parity 1-9) were divided randomly into three groups (no intervention (Control), 300 ml sodium chloride (Placebo) and 300 ml of phytotherapeutic agent (Phytotherapeutic)). Several sow-related parameters were assessed such as, parity, Body Condition Score (1-5), birth induction (Yes/No), and feed intake. On days 2, 3, 5, 7 and 21 postpartum, uterine involution was assessed by measuring the diameter on three locations of the uterine horns using ultrasound. The mean uterine diameter changed from 36.4 ± 6.5 mm on day 2-20.4 ± 5.9 mm on day 7 (reduction of 43.81 %) and 14.0 ± 3.2 mm on day 21 (reduction of 61.15 %). No significant differences between the groups and the regression of uterine involution were detected. However, birth induction had a positive effect on uterine involution, increasing the relative uterine involution by 8 %, whereas lack of appetite postpartum, lead to a decrease of 7 % until day 7. An suboptimal BCS (≤2
≥4) and a parity ≥2 lead to a reduction of uterine involution regression on day 21 by 7 and 5 %. In conclusion, a single postpartal intrauterine application of a phytotherapeutic agent demonstrated no significant impact on uterine involution, while sow-specific and management factors remained pivotal.