For diarrhea caused by a stomach virus or a meal that didn't agree with you, try the BRAT diet, says James Lee, MD, gastroenterologist with St. Joseph Hospital in Orange, Calif. "Many different things can cause diarrhea, such as Crohn's disease or colitis," so see your doctor if symptoms continue for longer than two weeks or sooner if signs of dehydration appear, or if diarrhea is accompanied by fever, blood, severe pain, or severe nausea and vomiting.
Constipation can occur when not eating enough fiber-rich whole grains, fruits, and veggies, which stimulate digestion. "Adults need between 25 and 30 grams of fiber a day," says Dr. Lee.
: High-fiber whole grain breads, nuts, beans, prunes, oatmeal, flaxseed, broccoli, pears, and apples. (Here are the 20 best foods for fiber
.) Drinking six to eight glasses of water per day also helps get things moving, says Dr. Lee.
Worst foods: Chocolate, dairy products, iron supplements, narcotics (pain medications) and some blood and anti depression medications may worsen constipation.
You're feeling nauseous
Feeling queasy makes all foods sound unappealing, but the right ones can ease symptoms by calming stomach acids, says Dr. Lee. "In general, keep food portions small and odors to a minimum."
Best foods: Saltine crackers or pretzels can help, says Dr. Lee, as does small quantities of dry toast or cereal. Ginger or lemon tea, fresh or frozen lemon slices, and peppermint also work.
Worst foods: Greasy, spicy, or oily foods, caffeine, alcohol, and carbonated drinks can make nausea worse.
It hurts to swallow
When you have a sore throat, several foods can coat your throat and soothe the pain, says Lauren Slayton, RD, founder of Foodtrainers.com and author of The Little Book of Thin (Perigee 2014).
Best foods: Combine peppermint tea (lukewarm, not hot)—which has analgesic and anesthetic effects—and Manuka honey, which is known for its wound-healing properties. Soft, creamy foods such as cream soups, mashed potatoes, yogurt, scrambled eggs, and custards are also soothing.
Worst foods: Avoid hot liquids and hard, scratchy foods such as potato chips, nuts, and granola. The acidic juices from raw fruits and vegetables, as well as orange juice, grape juice, and lemonade can also irritate a sore throat.
Your entire body aches
Foods that ease muscle aches depend on the specific reason for the body aches, says Kristine Arthur, MD, internist at Orange Coast Memorial Medical Center in Fountain Valley, Calif. "For general muscle aches, food containing magnesium or calcium may help ease soreness," she says.
Best foods: Magnesium-containing foods include nuts, bananas, beans, leafy greens, and avocados. Foods high in calcium such as canned salmon, yogurt, dark-green leafy greens, and orange juice fortified with calcium also lessen muscle cramping and pain.
Worst foods: Anything that dehydrates you can worsen muscle aches, says Dr. Arthur, particularly alcohol and caffeine.
Your head hurts
Dehydration is one of the leading causes of headaches, says Dr. Arthur, so it's best to treat that cause first and see if it relieves your pain.
Best foods: Water and other fluids are your best bet. "Drink a bottle of water and wait 20 minutes to see if you feel better," says Dr. Arthur. Caffeine is known for drying you out, but ironically, it can help in small doses. "But for each cup of tea or coffee, drink an equal amount of water to avoid dehydration," Dr. Arthur says.
Worst foods: Headache-triggering foods include artificial sweeteners, MSG (found in sauces and soy sauce), aged cheeses (blue, stilton) that contain tyramine, plus chocolate, red wine, hot dogs, deli meats, and dried fruit. MSG is metabolized to glutamate, an excitatory neurotransmitter in the brain, says Dr. Arthur. Tyramine links to increased blood pressure, which can trigger headaches.
You have an earache
Earaches typically accompany other symptoms, says Dr. Arthur. "So they're not correlated with any food in general." Since they occur most often with upper respiratory infections, however, foods that clear up congestion can help earaches as well.
Best foods: Clear fluids and chicken soup ease congestion by loosening up mucous in nasal passages. Omega-3s found in salmon and nuts decrease inflammation, and vitamin C found in dark leafy greens, berries, and citrus boost the immune system, says Dr. Arthur.
Worst foods: Dairy can thicken phlegm and worsen congestion, with the exception of yogurt, which contains probiotics, says Dr. Arthur. "Stay away from processed and packaged foods, too, which increase inflammation and lengthen the recovery process."
You're red and itchy
A rash could be a symptom of an allergy, says Dr. Arthur. "Keep a detailed food journal to look for links to foods that seem to trigger a rash."
Best foods: Omega-3 containing foods such as fatty fish (salmon, sardines) and walnut and flax seed oils, as well as foods high in protein are all important for skin health, says Dr. Arthur. "Skin is made up of proteins, so a diet adequate in protein is necessary for skin protein synthesis."
Worst foods: The most common foods that cause itching are nuts, chocolate, fish, tomatoes, eggs, berries, soy, wheat, and milk, says Debra Jaliman, MD, dermatologist and author of Skin Rules: Trade Secrets from a Top New York Dermatologist ($9, amazon.com).
You have a runny nose
When you have a cold, the worst symptom might be a nose that just won't stop running. Aside from taking a steamy shower, Slayton suggests drinking warm tea—it may not slow down the drip, but a soothing tea will make you feel better.
Best foods: Try Wakaya ginger tea, suggests Slayton. Ginger contains antioxidant and anti-inflammatory properties that may help clear up a cold faster than just waiting it out. "Apple cider and lemon in water works well, too," she says.
Worst foods: Spicy foods can cause an immediate runny nose (which then turns into congestion), as may alcohol.
You're stuffed up
A cold, flu or sinus infection can irritate and inflame blood vessels in your nose, making it hard to breathe. Aside from inhaling steam from a hot shower or using a humidifier, if you're stopped up due to mucous, some foods can help.
Best foods: Slayton recommends "golden milk," which includes turmeric, a spice known for its anti-inflammatory properties. Place 2 cups of coconut or almond milk in a saucepan with 1 tsp dried turmeric, 1 tsp dried ginger, a dash of black pepper and honey to taste. Bring to a simmer, allow to sit for 10 minutes and serve warm.
Worst foods: Skip dairy, spicy foods, and sugar, all of which can aggravate symptoms, says Slayton.