Dehydration.

Dehydration, in simple words, is shortage of water in the body.
Causes
Dehydration can happen due to:
Insufficient water/liquid intake or
Excessive loss of liquids due to diarrhoea, sunstroke or vomitings.
Signs & Symptoms
Furious thirst.
Dizziness, nausea (vomiting sensation.)
Extreme exhaustion.
Loss of elasticity of skin and wrinkling.
Herbal Medicines
In mild cases of dehydration, the treatment is following the simple thumb rule of replacing the lost fluid. Non-alcoholic drinks may be given in plenty. Coconut water, barley water, sugarcane juice or glucose-water are the best. Nowadays oral rehydration sachets are freely available. They are easy to use, when duly mixed as per the instructions laid down on the cover. Alternatively, one can use a home made rehydrating solution containing a pinch each of sugar and salt in a cup of water.
In severe cases of dehydration, intravenous fluids are essential, and immediate hospitalisation is a must.
Further, dehydration being more serious in children, medical advice is very essential in such cases.
Ayurvedic Remedies
Shadanga Paneeyam, an oral liquid, 20ml + 50ml water should be given as required orally. It is cooling and rehydrative.