Any herb, even the safest and most researched of herbs, can affect different people differently. Much in the same way that some people get horrendous allergic reactions to strawberries, milk, and plant pollen, some people are adversely affected by even the most benevolent of herbs. Though it is a rare and unusual occurrence, whenever such a reaction is reported, it makes national headlines. Were drug reactions reported with the same fervor, we'd all be terrified of aspirin and cough syrup. However rare these reactions to herbs may be, though, it is always wise to be cautious when using an herb for the first time.

Perform small-dose tests. Use the herb in small amounts at first, to see how it works for you and your child. A good safety measure is a patch test. Make an herb tea, then "paint" a small amount onto the skin of the inner arm. Wait 24 hours; if you do notice any adverse reactions - a skin rash, itchy eyes, throat swelling, itchiness - discontinue use immediately. If the child does not experience an adverse reaction, you may administer a very small amount internally. Discontinue immediately if any signs of allergic reaction appear. You may wish to try the herb again, prepared in the same manner and administered in the same amount, after a few days. If the child again experiences discomfort, then I would attribute the effects to the herb or herbal formula and look for another, more compatible herb.