The view that ‘degenerative’neurological conditions such as amyotrophic sclerosis (ALS), Parkinson's disease and Alzheimer's dementia may be caused by environmental toxins has been strengthened by a recent report by Spencer et al. in Science 1. Male cynomolgus monkeys developed cortico-neuronal dysfunction, parkinsonian features and behavioral changes with chromatolysis and degeneration of motor neurons following daily oral doses of β-N-methylamino-l-alanine (BMAA), a ‘free excitatory’neurotoxic amino acid present in the seeds of Cycas circinalis.