I returned to work three months ago when my baby was six months old and since then I've been constantly moderately ill (vomiting, colds, sore throats, running or blocked nose and now conjunctivitis). What can I do to boost my immune system?

Your body has been working hard for 18 months, creating and nurturing a new life. In pregnancy and through breastfeeding the baby gets what it needs and leaves you with the leftovers. B complex vitamins, vitamin C and essential fatty acids - all important for immunity - are used up more rapidly when you are stressed. Low reserves of zinc, iron and magnesium can cause low immunity, fatigue, mood swings, depression and a susceptibility to stress. It is crucial to keep well nourished at all times. I could recommend general immunity boosters such as Potter's Echinacea and Garlic, MicrOrganics Hawaiian Spirulina, Comvita Elixir and the new All-Terrain Immunity tincture from Barefoot Doctor. However, optimum immunity depends on holistic health - all body systems need to be in balance. The best way to achieve this is treatment specific to your needs with a therapist such as a naturopath (General Council and Register of Naturopaths, 01458 840072).

I am 83 years old and enjoy very good health, but I have recently developed a persistent dry cough which means I am unable to visit the cinema, theatre or any gathering. Antibiotics cleared it up for three weeks but it is back. Can you help?

A long, mild autumn followed by a sudden cold spell has given rise to many coughs. Apart from the general immunity boosters mentioned above, essential fatty acids are necessary to combat dryness in the membranes of the throat and lungs. In the elderly these can be particularly dry; consequently there is a lack of the watery mucus needed to shift the infection. Paul Hambly's Cough And Cold Mix includes balm of Gilead to soothe the membranes, elecampane and thyme as expectorants and natural antibiotics, plus the anti-inflammatory action of plantain and liquorice. Coltsfoot helps tickly coughs and chest problems. For Essential Balance essential fatty acids, Cough And Cold Mix and coltsfoot capsules, contact Paul Hambly's Herbal Dispensary on 01892 783027 (hamblys.net).

· Emma Mitchell is a natural health therapist. Before following Emma's recommendations, you should consult your GP about any medical problems or special health conditions. Send your questions to Wellbeing, Guardian Weekend, 119 Farringdon Road, London EC1R 3ER. Email: ask.emma@theguardian.com.