These are grouped together because they usually occur together, though they may occur independent of each other. They are symptoms of the diseases affecting the digestive system.
The major threat posed by vomiting and diarrhoea is the depletion of water and electrolytes (salt / minerals) in the body. The more severe they are, the more rapidly the depletion.
Salt and water are important for proper body functioning. There is critical level the depletion should not go beyond. This is the reason prompt presentation in the hospital for appropriate medical intervention is very important.
The most important thing in this condition is to prevent losing significant amount of water and salt. So, when affected by vomiting or diarrhoea or both, preparing salt-sugar solution to take at frequent interval is life-saving.
This has been simplified in the ready-made oral rehydration therapy. This is added to water as recommended on the leaflet. This oral rehydration therapy is even more important when diarrhoea and vomiting involves children because their bodies contain more water than that of adults.
The younger the child is, the more likely he or she will be affected early by the effects of vomiting and diarrhoea. For parents with little children, this oral rehydration therapy should be available at home at all time.