Heatstroke: "an onion in the pocket; raw mango drink cures it".

What is right: fluids and salt matter. In hot weather fluids and salt matter, and summer drinks can be part of staying hydrated. Made with water, a little salt and some sugar, raw mango drink fits the national advisory's category of "fruit juices with a little added salt"; the advisory does not name it, so that is an inference. [S5]

Heatstroke is an emergency. India's National Programme on Climate Change and Human Health calls heat stroke "a life-threatening, time-sensitive condition": a core temperature of 40°C or higher causes brain dysfunction and can damage the lungs, heart, liver, kidneys and blood clotting, with a mortality rate of 40% to 64%. Its rule is "cool first, transport second", with cooling started within 30 minutes and continued on the way. The steps: move to shade or indoors, call emergency services, lie down with feet raised, give cold water to sip if conscious, remove outer clothing, spray with cold water, apply damp sheets or ice packs to the torso, armpits, neck, head and groin, and fan. It advises against paracetamol or aspirin, against relying on ice packs alone, and against an air-conditioned room as the only cooling. [S3] The national facility guideline agrees: start cooling at once, "Avoid Paracetamol or NSAIDS", and "Cool and transport fast to nearest health care facility". [S4]

The signs. Mayo Clinic: heatstroke is generally present at a core temperature of 40°C or higher, with confusion, slurred speech, seizures or coma, hot dry skin or heavy sweating, fast breathing and a rapid heartbeat; without prompt treatment it can cause brain and organ damage or death. While waiting for help, move the person to shade, remove extra clothing and cool them by any means, such as a cool shower, hosing or sponging, fanning while misting, or ice packs and wet towels to the head, neck, armpits and groin. [S6]

Prevention, the official version. The 2026 national heat advisory recommends drinking water even when not thirsty, ORS, and home drinks such as lemon water, buttermilk or lassi, and fruit juices with a little added salt; not going out between 12 noon and 3 pm; light, loose cotton clothing and a head covering; and never leaving children in a parked vehicle. It lists danger signs (confusion, seizures, hot red dry skin, 40°C or more, fainting, vomiting; in children, refusal to feed, lethargy and less urine) and says "Heatstroke is a medical emergency!" and "Call 112". It does not mention onion or raw mango drink. [S5]

The onion. No study of an onion carried on the body, rubbed on the skin or eaten to prevent heat illness was located, and no guideline opened mentions it. There is no plausible way for an onion in a pocket to change core body temperature.

"Cures" is the dangerous word. No study of raw mango drink for preventing or treating heat illness was located. It cannot treat heatstroke, which requires cooling, and a confused or drowsy person should not be made to drink. [S3] The word "cures" can lead a family to give a drink to a confused, overheated person instead of cooling them and calling for help.