The roots of Sweet Flag (Acorus calamus) have stimulating, euphoric, aphrodisiac and mildly hallucinogenic effects.
For a clear, uplifting effect: mix 1 tablespoon in a cup of hot water and drink this on an empty stomach. For a stimulating effect: soak 20 grams of the root for a while and then boil it for a couple of minutes in half a litre of water. Strain and drink a couple of cups. For a mind-expanding effect: raise the dosage as required.
Do not use Sweet Flag if you're pregnant, as some sources say this could bring about a premature delivery.