Valerian and hops are traditionally used as sleep-inducing aids. Alertness reduces gradually with the prolongation of wakefulness through the release of endogenous adenosine in the frontal basal cortex. Valerian has an adenosine-like action and supports the readiness to fall asleep. The control of the sleep-wake rhythm induces sleep when the time-related interaction is operating properly. The control is closely related to endogenous melatonin secretion. Hops act in a similar way to melatonin. Therefore, the efficacy of a valerian and hops combination in sleep disorder can scientifically be explained.