Precocious puberty (PP) in girls is common and mostly idiopathic due to precocious activation of the gonadotropic axis. In this review, we find it important to distinguish the normal variant of slightly early puberty from rapidly progressive cases. Abnormal harmony of puberty more likely warrants a pathological condition. In girls aged about eight years with confirmed idiopathic PP, observation for 3-6 months is reasonable in order to identify clinically progressive cases, who will benefit from intervention with an gonadotropin-releasing hormone agonist.