Alkaloids are organic compounds containing nitrogen that are produced by some plants, bacteria, fungi, and animals. Several alkaloids are produced by fungi, including ergot alkaloids from the claviceps fungi that grow on rye and other grains. Ergotamine is an ergot alkaloid used medicinally as a vasoconstrictor. Psilocybin mushrooms contain the hallucinogenic compound psilocybin. Other fungal alkaloids include oxaline from Penicillium fungi and paramine from Neotyphodium fungi.