A family of compounds which function as selective ligands for the serotonin receptor 2B (5-HT2B) is identified. Some of the compounds are synthetic non-natural ligands which have a relatively strong interaction with 5-HT2B compared to naturally occurring compounds (some of which are identified for the first time herein as ligands for 5-HT2B). Because the compounds, both naturally occurring and synthetically produced, function as ligands for 5-HT2B they will have application in, for example, the treatment and/or prevention of nervous system disorders such as Alzheimer's disease.