What causes nausea or vomiting?
The causes of nausea and vomiting are quite similar. Many things can bring on nausea. Some common causes are seasickness and other motion sicknesses, early pregnancy, intense pain, exposure to chemical toxins, emotional stress (fear), gallbladder disease, food poisoning, indigestion, various viruses, and certain smells or odors.
The causes of vomiting differ according to age. For adults, vomiting is commonly a result of a viral infection and food poisoning, and occasionally a result of motion sickness and illnesses in which the person has a high fever. For children, it is common for vomiting to occur because of a viral infection, food poisoning, motion sickness, overeating or feeding, coughing, and illnesses in which the child has a high fever. Although rare, blocked intestines can cause vomiting, most typically in early infancy.
Usually vomiting is harmless, but it can be a sign of a more serious illness. Some examples of serious conditions that may bring on nausea or vomiting include concussions, encephalitis, meningitis, intestinal blockage, appendicitis, migraine headaches, and brain tumors.
Another concern with vomiting is dehydration. Adults have a lower risk of becoming dehydrated because they can usually detect the symptoms of dehydration (such as increased thirst and dry lips or mouth). Children have a greater risk of becoming dehydrated, especially if the vomiting occurs with diarrhea, because young children may often be unable to tell an adult about symptoms of dehydration. Adults caring for sick children need to be aware of these visible signs of dehydration: dry lips and mouth, sunken eyes, rapid breathing or pulse; or in infants, decreased urination, and a sunken fontanelle (soft spot on top of the baby's head).