Wormwood (artemisia asintium) has a bad reputation but after some research and many tests on my body i can say that i have not found it to be dangerous and i have ingested a lot of herb powder !
The bad reputation of Wormwood is due to the alcohol "absinthe" which is a blend of artemisia absintium and artemisia cina.
Wormseed (artemsia cina) has been reported to produce damages on the liver, on the kidneys, blindness, even in small doses.
The safe approach is to start to ingest a very small dose and then wait a few hours to see the effects and then increase the dose progressively. But some herbs are very toxic even in small doses and must be avoided.