El objetivo de este estudio experimental, controlado a doble ciegas, fue evaluar el efecto del White Chestnut sobre los pensamientos intrusos indeseados en una muestra de adultos supuestamente sanos que reportaron presentarlos de forma regular. La muestra quedó conformada por 70 participantes (47 mujeres y 23 hombres), con un rango de edad de 20-60 (36,42 ± 10,52) años, asignados aleatoriamente a 2 grupos: White Chestnut y placebo (n1= n2= 35). Para la evaluación de los cambios se utilizó el White Bear Suppression Inventory. Se observaron diferencias significativas intergrupos para la calificación global de la prueba [t (68)= -2,16, pA controlled double-blind experimental study was conducted to evaluate the effect of white chestnut on unwanted intrusive thoughts in a sample of seemingly healthy adults who reported having these thoughts regularly. The sample was composed of 70 participants (47 women and 23 men) aged 20-60 (36.42 ±10.52), randomly assigned to one of two groups: white chestnut and placebo (n1=n2=35). The White Bear Suppression Inventory was used for change evaluation. Significant differences were found between the two groups in the global test score [t (68)= -2.16, p<0.05 and d= 0.51], with a predominance of the factor measuring intrusive thoughts [t (68)= -2.84, p< 0.01 and d= 0.67]. Results suggest that white chestnut may be an effective resource for reducing unwanted intrusive thoughts, its effect being clearly distinguishable from that of the placebo.