ch'an su, or as a psychedelic, by smoking or orally ingesting Bufo toad venom or dried Bufo skins. The use of chan'su and love stone (a related toad venom preparation used as an aphrodisiac in the West Indies) has resulted in several cases of poisoning and at least one death. The practice of orally ingesting toad venom has been referred to in popular culture and in the scientific literature as toad licking and has drawn media attention. Albert Most, founder of the defunct Church of the Toad of Light and a proponent of spiritual use of Bufo alvarius venom, published a booklet in 1983 titled Bufo alvarius: The Psychedelic Toad of the Sonoran Desert which explained how to extract and smoke the secretions. Bufotenin is also present in the skin secretion of three arboreal hylid frogs of the genus Osteocephalus (Osteocephalus taurinus, Osteocephalus oophagus, and Osteocephalus langsdorfii) from the Amazon and Atlantic rain forests. Anadenanthera seeds Bufotenin is a constituent of the seeds of Anadenanthera colubrina and Anadenanthera peregrina trees. Anadenanthera seeds have been used as an ingredient in psychedelic snuff preparations by indigenous cultures of the Caribbean, Central and South America since pre-Columbian times. The oldest archaeological evidence of use of Anadenanthera beans is over 4,000 years old. Other sources Bufotenin has been identified as a component in the latex of the takini (Brosimum acutifolium) tree, which is used as a psychedelic by South American shamans, and in the seeds of Mucuna pruriens. Bufotenin has also been identified in Amanita citrina, A. porphyria, and A. tomentella. Pharmacology Uptake and elimination In rats, subcutaneously administered bufotenin (1–100 μg/kg) distributes mainly to the lungs, heart, and blood, and to a much lesser extent, the brain (hypothalamus, brain stem, striatum, and cerebral cortex), and liver. It reaches peak concentrations at one hour and is nearly eliminated within 8 hours. In humans, intravenous administration of bufotenin results in excretion of (70%) of injected drug in the form of 5-HIAA, an endogenous metabolite of serotonin, while roughly 4% is eliminated unmetabolized in the urine. Orally administered bufotenin undergoes extensive first-pass metabolism by the enzyme monoamine oxidase. Lethal dose The acute toxicity () of bufotenin in rodents has been estimated at 200 to 300 mg/kg. Death occurs by respiratory arrest. In April 2017, a South Korean man died of bufotenin poisoning after consuming toads that had been mistaken for edible Asian bullfrogs, while in Dec.