In large doses, however, the oil is poisonous, causing dilated pupils, vomiting, stupor, collapse and kidney and liver damage. The oil has been applied externally to control lice and treat insect bites, though it can cause skin irritation in some people. The essential oil is also used in soaps, the coarser kinds of perfumery, toothpastes, soft drinks etc. The growing plant repels mosquitoes and other insects, so it is a beneficial companion plant in the garden. Dried leaves will add a pleasant but delicate scent to the room whilst also helping to keep insects away.
Propagation is fairly simple from seed.
If you can obtain it, fresh seed will give the best results and this should be sown immediately in a cold frame. It should germinate in the spring. If you can only obtain stored seed then this will need four months cold stratification at 4 c. As soon as they are large enough to handle, prick out the seedlings into individual pots and grow them on in the greenhouse for at least their first winter before planting them out. If they are well-rooted they can be planted straight out into their permanent positions but if the root system is rather sparse it is best to pot them up and place them in a lightly shaded place in the greenhouse until they are growing away strongly.