9-Methyl-beta-carboline (9-Me-BC, also 9-methylnorharmane) is a beta-carboline, one of a class of pyridoindoles derived from tryptophan and its derivatives that occur in sources such as cooked meat and tobacco smoke and have been detected in human brain, cerebrospinal fluid and plasma. Many beta-carbolines have been studied as potential neurotoxins; 9-Me-BC was reported in 2008 as an exception, with protective and differentiating effects in primary dopaminergic culture. The published literature is small. It consists mainly of primary midbrain and astrocyte culture studies and a few rat studies, together with photochemical work on 9-methyl-beta-carbolines as photosensitisers.