Does your child ever complain of a tummy ache? Try fennel (xiao hui xiang), a Chinese medicinal used to treat stomachache and colic. Make a tea by pouring boiling water over 2 tsp. of crushed fennel seeds, let cool and then drink. You can also get fennel extract from an herbal practitioner.
If Irritable Bowel Syndrome or "nervous stomach” is what troubles your child, try enteric-coated peppermint capsules such as Pepogest brand. Peppermint oil (called bo he in Chinese/Pinyin) helps ease spasms but shouldn't be used for acid reflux.
Probiotics from the refrigerated section of the health food store will also help over the short and long terms, especially if your child has had to take antibiotics, and they now even make them specifically formulated for kids.