Rosemary and Thyme

Rosemary and Thyme are all known and valued for their antimicrobial and aromatic effects. The antimicrobial effects can be of use in various infections (most often pulmonary), whilst the aromatic qualities tend to have an effect on the emotions and the brain.


Rosemary has been traditionally used as a tonic for the digestion and for the head. It has a stimulating effect on both. A sprig of rosemary made into a tea with boiling water can have a useful effect for clearing the head after a heavy meal. A small research trial looked at the effect of inhaling rosemary essential oil, demonstrating, amongst other effects, an increase in alertness. Possibly for similar reasons, Rosemary may be of value in dementia. A wide range of research confirms the antimicrobial activities, though of particular interest are those pointing to possible use again drug resistant bacteria. Rosmary is also known for its antioxidant effects – an interesting bit of research demonstrated that cigarettes with rosemary extract in the filter decreased the quantity of a tumour forming chemical by >70%. There is a strong traditionally link between grief and rosemary. In my own experience, it can be useful to help lift people out of an overly heavy melancholia that can come following loss.

Cautions: Rosemary is a strong herb – this is one to use with care. I advise caution in pregnancy, breast feeding and if attempting to get pregnany. Use only under supervision if epileptic, with high blood pressure or (since it is mentally stimulating) to those who are already too mentally stimulated! I have noticed in some of my patients that taking rosemary in the afternoon/evening can lead to increased awareness of dreams. The essential oil should not be used undiluted on the skin, and may cause a rash in a small percentage of people. Care should be taken if anaemis or taking iron supplements for anaemia, since Rosemary may interfere with iron absorption.


Thyme is strongly aromatic and stongly antimicrobial. I use thyme internally for coughs – where, combined with Liquorice or Honey is makes a wonderful cough syrup. Externally thyme cream is antifungal and stimulating. One common use is for athletes foot. There has been much research concerning the antibiotic effects of thyme, and as with Rosemary, of particular interest is the potential activity against antibiotic resistant bacteria. Thyme is also active against Herpes simplex and thus may be a useful topical treatment for Herpes infections. A well designed trial in Germany demonstrated the efficacy of a Thyme and Primrose preparation in acute bronchitis.

Cautions: Caution and moderation is advisable in pregnancy and breastfeeding. Thyme oil should not be used undiluted since it can result in a rash. Exposure to high doses of the essential oil can cause headaches.


Evidence sources: The descriptions here are drawn from traditional sources, biomolecular studies, personal clinical experience and small scale clinical trials. This page is intended for solely for information purposes and not as a substitute for personal advice from a qualified health care provider. For cautions when self-prescribing herbs see click here.