If your diarrhea is mild, you may not need to take anything. Or you can take an over-the-counter medicine such as bismuth subsalicylate or loperamide, which are available as liquids or tablets. Follow the instructions on the package.
You also need to stay hydrated. You should drink at least six 8-ounce glasses of fluids each day. Choose fruit juice without pulp, broth, or soda (without caffeine). Chicken broth (without the fat), tea with honey, and sports drinks are also good choices. Instead of drinking liquids with your meals, drink liquids between meals. Sip small amounts of fluids often.