Sage plant and roots. This plant has been grown hydroponically (in water) in a laboratory. Here, the mature root system is seen, along with a healthy growth of leaves. Oils from the leaves of the sage plant are being investigated for their medicinal effects. Sage has been used by herbalists for centuries to improve memory, and a medical trial in 2003 showed improved short-term memory recall in those given sage oil tablets. It is thought that sage oil tablets could slow the onset of Alzheimer's disease. Sage species being investigated include Salvia lavandulaefolia and Salvia officinalis. This research is being carried out at laboratories at the Universities of Newcastle and Northumbria, UK, as part of work by the Medicinal Plant Research Centre.