Qinghao contains artemisinin, which has proven a safe and effective malaria treatment. The plant is known also as sweet wormwood or by its botanical name, Artemisia annua. "The yields from demonstration farms have given satisfactory results," according to the head of the ministry's Department for Development of Thai Traditional and Alternative Medicine.

Dr Wichai Chokewiwat said yesterday the plant indigenous to China contained artemisinin, which can suppress malaria.

Previous test crops grown here did not yield enough artemisinin to make it commercially viable.

Last year the department started to identify the most appropriate strains of Qinghao for commercial use. The four demonstration farms grew Qinghao which produced high levels of artemisinin. "This is good news," Wichai said yesterday.