According to The College of Family Physicians of Canada, vomiting and diarrhea can be caused by a number of things, including bacteria, viruses, eating too much or too fast, eating too many sweets and even motion sickness. How you deal with the problem depends partly on what caused it, so it's important to try to determine the cause. According to the American Academy of Family Physicians, the two most common reasons for vomiting and diarrhea in adults include stomach flu and food poisoning.
Drink water, tea and clear broth a little bit at a time. This should comfort your stomach and keep you hydrated at the same time. Drink slowly and stop if you're feeling nauseous or having difficulty keeping the liquid down. The Atlantic Health Sciences Corporation recommends avoiding solids completely and only drinking until you feel better.
Try an over-the-counter anti-vomiting medication. The American Academy of Family Physicians recommends meclizine and cyclizine to prevent motion sickness and dizziness that might be causing the vomiting or posphorylated carbohydrate solution to ease stomach irritation and control nausea and gagging.
Take anti-diarrhea medication such as Imodium AD or Pepto-Bismol, as recommended by medical site GI Health. These over-the-counter products should only be used if the diarrhea persists for more than a day or two. For the first 24 hours, don't try to stop diarrhea, as it might be a way for your body to get rid of toxins or viruses.
Eat only light foods once the nausea is gone. According to The College of Family Physicians of Canada, starchy foods are best to recover from diarrhea. Try bread, sugar-free cereals or crackers. Avoid anything too sweet or high in fat, as this can worsen the problem.
See a doctor if diarrhea and vomiting last longer than two days or if you’re experiencing additional symptoms such as lethargy, blood in the vomit and fever over 101 degrees Fahrenheit.