Alkaloids are a group of naturally occurring chemical compounds that mostly contain basic nitrogen atoms, produced by a large variety of organisms including bacteria, fungi, plants, and animals. This group also includes some related compounds with neutral and even weakly acidic properties. Compounds like amino acid peptides, proteins, nucleotides, nucleic acid, amines, and antibiotics are usually not called alkaloids. Alkaloids have a wide range of pharmacological activities including antimalarial, antiasthma, anticancer, cholinomimetic, vasodilatory, antiarrhythmic, analgesic, antibacterial, and antihyperglycemic activities. Many have found use in traditional or modern medicine, or as starting points for drug discovery. Other alkaloids possess psychotropic and stimulant activities, and have been used in entheogenic rituals or as recreational drugs. Alkaloids can be toxic too. Although alkaloids act on a diversity of metabolic systems in humans and other animals, they almost uniformly evoke a bitter taste.