Objectives To evaluate the effects and safety of the aqueous extract of the dried, immature fruit of Poncirus trifoliate (L.) Raf. (Rutaceae) (PF) in stroke patients with constipation. Methods A total of 22 patients were recruited. Patients were interviewed about the clinical informations, constipation score and Bristol stool form scale at twice, before intake PF and after intake PF 2 weeks. The total and segmental colon transit time (CTT) were measured by using radio-opaque markers (Kolomark$^{(R)}$). The degree of stool retention was evaluated by the plain abdominal radiography and was scored by Leech score. Results Before intake PF, constipation scores ranged from 3 to 12, average $6.54{\pm}2.87$ and Bristol stool form scale ranged from 1 to 6, average $3.86{\pm}1.21$. CTTs were $9.05{\pm}6.89hours$, $14.29{\pm}10.68hours$, $12.11{\pm}7.19hours$ and $35.40{\pm}19.5hours$ in the right, left, rectosigmoid and total colon, respectively. Stool retention score was $2.45{\pm}0.61$, $2.3{\pm}0.86$, $1.9{\pm}0.85$, $6.65{\pm}1.56$ in the right, left, rectosigmoid and total colon, respectively. After 2 weeks, constipation scores ranged from 2 to 8, average $4.28{\pm}2.05$ and Bristol stool form scale ranged from 1 to 6, average $4.17{\pm}1.04$. CTTs were $7.41{\pm}8.86hours$, $11.12{\pm}9.12 hours$, $8.83{\pm}8.75hours$ and $27.3{\pm}20.2$ hours in the right, left, rectosigmoid and total colon, respectively. Stool retention score was $1.9{\pm}0.64$, $2.2{\pm}0.69$, $1.4{\pm}0.88$, $5.5{\pm}1.39$ in the right, left, rectosigmoid and total colon, respectively. There were statistically significant difference in the total and rectosigmoid colon CTT and constipation score, Stool retention score in right and rectosigmoid colon (p<0.05) after PF therapy. Conclusions These results suggest potential for PF therapy in stroke patient with constipation.