Although there are no specific reports of toxicity, it is suggested that no more than two (2) drops be taken internally. There is the potential for irritant or allergenic skin reactions with the topical use of lavender oil as it has been found to be cytotoxic to human skin cells in vitro (endothelial cells and fibroblasts) at a concentration of 0.25% (v/v), possibly due to membrane damage. The activity of linalool was found to reflect the cytotoxicity of the whole oil, whereas the cytotoxicity of linalyl acetate was found to be higher than that of the oil, suggesting suppression of its activity by an unknown factor in the oil.
Controlled studies are not available; therefore, interactions are based on evidence of activity and are largely theoretical and speculative.
Theoretically, lavender can potentiate the effects of sedatives, so observe patients taking this combination closely — beneficial interaction possible under professional supervision.
Lavender tincture may have additive effects when used with these medicines — beneficial interaction possible.
No restrictions known for external use.
Safety of internal use has not been scientifically established.