Objective To observe the therapeutic effect and adverse reactions of Biejia Shengxue Pill（ Turtle Shell Blood- Engendering Pill） for primary myelofibrosis. Methods Totally 120 patients with primary myelofibrosis were selected and orally taken 8 g Biejia Shengxue Pill twice to three times daily for 3 months. The results of blood routine examination

liver

spleen

bone marrow examination and adverse reactions were observed. Results After treatment

there were 39 cases much improved

47 cases improved

and 34 cases invalid

with a total effective rate of 71. 67%. The counts of hemoglobin（ HGB）

white blood cell（ WBC） and platelet（ PLT） were obviously increased in 30 patients with HGB reduction

WBC reduction and PLT reduction

especially HGB and WBC（ P < 0. 05）. The PLT count was significantly decreased after treatment in patients with increased WBC and PLT（ P < 0. 05）. There was a significant difference between before and after treatment in splenomegaly condition in 114 patients with splenomegaly（ P < 0. 05）. There was no significant difference between before and after treatment in hepatomegaly in 81 patients with hepatomegaly（ P > 0. 05）. The biopsy showed that myelofibrosis was significantly improved after treatment（ P <0. 05）. There were 11 patients with a few skin bleeding and 7 patients with gastrointestinal reactions but the adverse reactions disappeared when reducing the dosage. Conclusion Biejia Shengxue Pill is effective for primary myelofibrosis with no serious adverse reactions.