The U.S. National Institutes of Health (NIH) states that lavender is considered likely safe in food amounts and possibly safe in medicinal amounts. NIH does not recommend the use of lavender while pregnant or breast-feeding because of lack of knowledge of its effects. It recommends caution if young boys use lavender oil because of possible hormonal effects leading to gynecomastia, and states that lavender may cause skin irritation and could be poisonous if consumed by mouth.
A 2005 review on lavender essential oil stated that "Lavender is traditionally regarded as a 'safe' oil and, although it was recently reported that lavender oil, and its major constituent linalyl acetate, are toxic to human skin cells in vitro, contact dermatitis to lavender oil appears to occur at only a very low frequency.
A 2007 study examined the relationship between various fragrances and photosensitivity, stating that lavender is known "to elicit cutaneous photo-toxic reactions", but does not induce photohaemolysis.