延药睡莲（学名：Nymphaea nouchali）又名蓝睡莲，为睡莲科睡莲属下的一个种。

Nymphaea caerulea, known primarily as blue lotus (or blue Egyptian lotus), but also blue water lily (or blue Egyptian water lily), and sacred blue lily (or sacred narcotic lily of the nile), is a water-lily in the genus Nymphaea. Like other species in the genus, the plant contains the psychoactive alkaloid apomorphine. It was known to the Mayan and Ancient Egyptian civilisations.