Tribulus terrestris: preliminary study of its diuretic and contractile effects and comparison with Zea mays.

Objectives: Tribulus terrestris L. (Zygophyllaceae) which is called Al-Gutub (in Iraqi dialect) or Quti;ba (in classical Arabic medicine), and Zea mays were both used alone or in combination by Iraqi herbalists to propel urinary stones. We studied the aqueous extract of the leaves and fruits of T.