Water lilies, particularly species such as Nymphaea caerulea (Blue Lotus) and Nymphaea alba (European White Water Lily), have a history of traditional use for their mild sedative and calming effects. In ancient Egyptian culture, Blue Lotus was used in ritualistic and medicinal contexts, sometimes infused in drinks or smoked for its purported ability to promote relaxation and aid sleep. In European folk medicine, extracts of Nymphaea alba were occasionally used as a remedy for nervousness and insomnia. These uses were largely based on anecdotal reports and empirical observations rather than systematic scientific investigation.

Despite this traditional use, scientific validation is limited. While some laboratory studies have identified the presence of alkaloids, flavonoids, and glycosides in water lily species, research on their pharmacological activity related to sleep or CNS depression in humans is sparse and preliminary. There are no robust clinical trials or comprehensive toxicological studies supporting water lily’s effectiveness for insomnia. Thus, the rating reflects that its use is primarily traditional, with weak supporting evidence and a lack of modern scientific validation.