A lyophilised hydroalcoholic extract of Melissa officinalis L. (Lamiaceae) has been evaluated for behavioral effects in mice. According to the traditional use of M. officinalis, sedative properties have been confirmed for low doses by the decrease of behavioral parameters measured in a non-familiar environment test (staircase test) and in a familiar environment test (two compartment test). With high doses, a peripheral analgesic activity was obtained by reducing the acetic acid-induced pain (writhing test); moreover, the plant extract induced the sleep in mice after treatment with an infrahypnotic dose of pentobarbital and potentialised the sleep induced by a hypnotic dose of pentobarbital.