If your baby is sick, offer small amounts of liquid. If you're breast-feeding, let your baby nurse. If your baby drinks formula, offer a small amount of an oral rehydration fluid or regular formula. Don't dilute your baby's formula.
If your older child isn't feeling well, encourage him or her to rest. Offer bland foods, such as soda crackers and toast. Plenty of liquids are important, too, including an oral rehydration fluid (EInfalyte, Pedialyte, others). Avoid apple juice, dairy products and sugary foods, which can make a child's diarrhea worse.
If you're struggling with diarrhea or vomiting, take it easy. Suck on ice chips or take small sips of water or clear sodas, such as ginger ale, or broths. Eat bland foods. Avoid anything that may irritate your stomach, including dairy products, fatty or highly seasoned foods, caffeine, alcohol, and nicotine.
Source: http://www.mayoclinic.com