Background: labour is ideally a joyous experience but can be associated with fetomaternal complications when prolonged thus any safe measure to prevent pronged labour is a well development for both the parturients and care givers. Objectives: To evaluate the effect of hyocine n-butyl bromide (HBB) on the duration of the first stage of labour in term pregnancies in NAUTH Nnewi. Methods: This is a double blind randomized trial involving 124 parturients who presented to the Labour ward of Nnamdi Azikiwe university teaching hospital at term in active phase of labour. They were randomly given an intramuscular injection of either 40mg of HBB or 2mls of water for injection as a placebo. The effect of HBB on duration of the stages of labour, maternal and neonatal complications were then evaluated.