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While it might be best to let the diarrhea resolve on its own, you may want to slow down the diarrhea using medication. You can take over-the-counter medications like bismuth subsalicylate or a fiber (psyllium) supplement. Adults can take 2.5 to 30g of psyllium a day in divided doses.  Bismuth subsalicylate can be used to treat "traveler's diarrhea" and contains mild antibacterial properties. Psyllium is safe to take during pregnancy or while breastfeeding. For vomiting associated with food poisoning, gastroenteritis and most other non-serious causes, take 1000–4000 mg of ginger (in four divided doses throughout the day. For example, take 250–1000 mg four times a day. Ginger has been used to treat nausea and vomiting of many different causes including chemotherapy-induced nausea, and the nausea of early pregnancy. Studies have shown ginger to be effective at relieving post-surgical nausea. It inhibits or suppresses certain types of brain and gut receptors that are related to the sense of nausea. Wash fresh ginger and cut off a two-inch piece. Peel the tan colored "skin" or peel to get to the pale ginger. Cut or grate it into small pieces to get a tablespoon. Add the ginger to two cups of boiling water. Cover the pot and boil it for another minute. Turn off the heat and let the ginger tea steep for three to five  minutes. Pour into a cup and add honey if you like. Drink four to six cups of ginger tea a day. Use fresh ginger, not ginger ale. Most ginger ales do not contain real ginger and contain high levels of sweetener. You should avoid sweeteners while nauseous because sugar generally makes you feel worse. While more research is needed, some herbs are believed to reduce viral or bacterial infections that cause nausea. If anything, herbal teas may simply let you relax and minimize your sense of nausea. To make herbal teas, add 1 teaspoon of dried powder or leaf and steep it in 1 cup of boiled water. You can add honey and lemon to taste. Use the following:  Peppermint Clove Cinnamon Take peppermint or lemon essential oil and place a drop of oil on both of your wrists and temples. Both peppermint and lemon oil have been traditionally used to treat nausea. Studies suggest that these oils reduce nausea by relaxation or by influencing the part of the brain that controls nausea.  Make sure you don’t have a skin sensitivity. Either put a single drop of oil on your wrist. If you have a sensitivity, you may experience a rash, redness or itching.  If so, try the other oil or another method. Only use essential oils, since candies or scents probably don't have real peppermint or lemon oil and are unlikely to have high enough levels of the oil to be helpful. Lie flat on your back and place pillows under your knees and neck for comfort. Put your hands palm down on your stomach below the rib cage. Place the fingers of your hands together so you can feel them separate. This will let you know you are doing the exercise correctly. Take a long, slow deep breath by expanding your belly, breathing through your diaphragm instead of your rib cage. The diaphragm creates suction that pulls more air into your lungs than can be achieved by expanding the rib cage. Research has shown that controlled, deep breathing can help relieve nausea. Other studies have indicated that breathing can help control nausea after surgery.
Take a diarrhea medication. Take a ginger supplement. Make a ginger tea. Make an herbal tea. Try aromatherapy. Practice controlled breathing.