Putrescine, or tetramethylenediamine, is a foul-smelling[2] organic chemical compound NH2(CH2)4NH2 (1,4-diaminobutane or butanediamine) that is related to cadaverine; both are produced by the breakdown of amino acids in living and dead organisms and both are toxic in large doses.[3][4] The two compounds are largely responsible for the foul odor of putrefying flesh, but also contribute to the odor of such processes as bad breath and bacterial vaginosis.[5] They are also found in semen and some microalgae, together with related molecules like spermine and spermidine.