Nausea is the sensation leading to the urge to vomit.
To vomit is to force the contents of the stomach up through the esophagus and out of the mouth. The rate with which dehydration takes place depends on the size of the person, the frequency of the vomiting, and whether or not there is also diarrhea . Infants with frequent vomiting and diarrhea are at the greatest risk for dehydration and need immediate medical attention. Signs of dehydration are increased thirst, infrequent urination or dark yellow urine , dry mouth, eyes that appear sunken, and skin that has lost its normal elasticity. This list is not all inclusive, and the causes are not presented in order of likelihood.