Sigma sells hygromycin $146.00/gm; $45.00/250 mg. Calbiochem sells hygromycin solution $62.00/1,000,000 units, there being 350-450 units/mg. According to my calculations, this means that one gets about 2.5 gm for this price. Are there other suppliers? Which do most people use? How stable are the aqueous solutions. Thanks for all advice. Chris Town.