Rosemary is generally recognised as safe for human consumption in quantities used as food. Consuming large amounts of rosemary may cause stomach and intestinal irritation, as well as seizures, owing to the high content of highly reactive monoterpene ketones, such as camphor. Topically, rosemary is not considered to be highly allergenic; however allergic contact dermatitis from rosemary has been reported, as has asthma from repeated occupational exposure. Rosemary essential oil should be diluted before topical application to minimise irritation.
Controlled studies are not available; therefore, interactions are based on evidence of activity and are largely theoretical and speculative.
Rosemary extracts are widely used as an antioxidant to preserve foods; however, the phenolic-rich extracts may reduce the uptake of dietary iron.
Separate doses by 2 hours.
DRUGS DEPENDENT ON P-GLYCOPROTEIN TRANSPORT
Theoretically, increased drug uptake can occur with those drugs dependent on P-glycoprotein transport. The clinical significance of this finding remains to be tested, although it has been suggested that this activity may be used to enhance the effects of chemotherapeutic agents.
Rosemary has been shown to have an anti-implantation effect in rats, without interfering with normal fetal development post-implantation. It has been used as an abortive in Brazilian folk medicine and is not recommended for use in pregnancy.