One is to promote uterine contraction before the birth of a baby, after playing the contraction will lead to strong contraction of the uterus causing severe abdominal pain, the dosage is normal to allow the uterus to return to normal regular contractions to promote the birth of the baby; however, if after using the contraction, the strong uterine contraction appears abnormal symptoms or the uterine contraction is too strong, it may lead to uterine rupture and life-threatening. There is also a kind of after the birth or abortion to promote the contraction of the uterus and promote the discharge of residual substances in the uterine cavity, after playing the contraction injection will appear bleeding increased resulting in the possibility of haemorrhage, the drug needs to be strictly in accordance with the clinical indications and instructions according to the dose, not to overdose the drug.