"Rhodiola rosea has an excellent safety profile, according to a the study reported in "The Journal of the American Botanical Council. The lethal dose of rhodiola rosea has been determined by animal toxicity studies to be 3,360 mg/kg. The toxic dose for an average 70 kg adult would be around 235,000 mg, and with clinical doses around 200 to 600 mg per day, patients likely have no need to worry about a fatal overdose."

Not sure if that is the toxicity data you mean.

I appreciate the additional studies. I can't actually make head or tails of this one: http://www.ncbi.nlm.nih.gov/pubmed/23430930

but the last two are certainly far more comprehensible to me, and meaningful.