Immediately stop what you are doing, remove from the hot environment, move to a well-ventilated or shaded area and remove outer clothing for rest. Also implement cooling measures (e.g. repeated wiping with cold water, cold water immersion, electric fans or air conditioning to help cool down). Drink cold salt water or beverages. If external cooling is not effective, you can use a 200ml enema of iced saline or take oral herbal remedies to relieve (heat) stroke.
Patients with general aura heatstroke and mild heatstroke can recover after on-the-spot care, but for severe heatstroke, call 120 immediately and take them to hospital while on-the-spot care and cooling.