Apomorphine (APO) is an aporphine derivative used in human and veterinary medicine. APO activates D₁, D(2S), D(2L), D₃, D₄, and D₅ receptors (and is thus classified as a non-selective dopamine agonist), serotonin receptors (5HT(1A), 5HT(2A), 5HT(2B), and 5HT(2C)), and α-adrenergic receptors (α(1B), α(1D), α(2A), α(2B), and α(2C)). In veterinary medicine, APO is used to induce vomiting in dogs, an important early treatment for some common orally ingested poisons (e.g., anti-freeze or insecticides). In human medicine, it has been used in a variety of treatments ranging from the treatment of addiction (i.e., to heroin, alcohol or cigarettes), for treatment of erectile dysfunction in males and hypoactive sexual desire disorder in females to the treatment of patients with Parkinson's disease (PD). Currently, APO is used in patients with advanced PD, for the treatment of persistent and disabling motor fluctuations which do not respond to levodopa or other dopamine agonists, either on its own or in combination with deep brain stimulation. Recently, a new and potentially important therapeutic role for APO in the treatment of Alzheimer's disease has been suggested; APO seems to stimulate Aβ catabolism in an animal model and cell culture, thus reducing the rate of Aβ oligomerisation and consequent neural cell death.