1993 Spring.Includes bibliographic references (pages 155-162).Many of the costly organic chemicals used by modern society are harvested from plants. A number of investigators have studied the use of plant cells in culture, rather than whole plants, as sources of some of the more valuable organic compounds. Before such processes can become a viable manufacturing option, a great deal more must be learned about the optimum conditions for growth and productivity of cells in culture. One aspect of this problem that has been relatively little studied is the effect of gaseous compounds on plant cell behavior. The most influential gases are believed to be oxygen, carbon dioxide and ethylene. One such organic compound of interest is the promising antimalarial artemisinin (known as "qing hao su" in China where it has been a folk remedy for centuries). It is produced in very low concentrations by Artemisia annua ("sweet wormwood"). The present author grew A. annua cells under a variety of dissolved gas conditions. Suspended cells were grown in tightly plugged flasks, in flasks under somewhat permeable conventional closures and under conditions of continuous headspace flushing with known gas mixtures. In the plugged culture tests, the usage rate of oxygen and production rates of carbon dioxide and ethylene per quantity of biomass were investigated. In the flushed headspace tests, cultures were exposed to various concentrations of the three key gases. The culture conditions were such that equilibrium between the culture liquid and gas headspace was assured. The growth rate of the cells and their production rates of artemisinin and related compounds were determined. These quantities were correlated as functions of the gas concentrations and compared with those exhibited by the conventional cultures