Normal root of Hyoscyamus niger was cultivated in four different culture systems; a flask, a stirred tank reactor, a mist bioreactor, and a unified mist bioreactor. The scopolamine/hyoscyamine contents of the roots in the various reactor configurations were at similar levels, but the growth rates were different. The dry weight of the root in the flask increased 21.4 times in 25 days, 12.9 times in the stirred tank reactor, and 4.76 times in the first mist bioreactor respectively. This low growth rate in the first mist bioreactor was probably due to limited nutrient supply of the air-carrier method. Root growth increased 9.29 times using the unified mist bioreactor in which mist can be sufficiently supplied without dilution of mist by air flow. It was estimated that a scale-up of over 10 dm(3) of reactor volume would not be effective if the air-carrier method were used in a mist culture system.