| The German Federal Institute for Risk Assessment (BfR) has conducted a risk assessment for Rhodiola rosea and concluded that there is no hazard potential at daily doses of 100-1,800 mg of rose root (mostly as root extract) |
Rose root contains, among other substances, the cyanogenic glycoside lotaustralin. When the plant is injured, cyanides (salts of hydrocyanic acid) can be cleaved from the cyanogenic glycosides. For humans, the lethal dose of prussic acid is 0.5 to 3.5 mg/kg body weight. Consequently, a 60 kg human would have to eat 2.4 kg to 17 kg of the raw Rhodiola rosea root to ingest a lethal amount of prussic acid. Therefore, no hazard potential can be derived. Due to the lack of data, no NOAEL has yet been established with respect to sustained intake of cyanides.
Overall, only a few intervention studies recorded possible adverse effects from the ingestion of rose root extract. In general, no adverse effects occurred. In one pilot study, taking 340 mg of rose root extract daily resulted in complaints of drowsiness and dry mouth. However, the results of this study should be considered with reservations, as only ten subjects participated and no control group was available for comparison.
Due to lack of sufficient data, extracts of Rhodiola rosea should not be taken by pregnant women, nursing mothers, or children.