Syncope, the medical term for fainting, is a temporary loss of consciousness caused by insufficient blood flow to the brain. This brief episode usually results from a temporary drop in blood pressure or heart rate, reducing the oxygen and nutrients supplied to the brain. The common practice of using a strong scent to revive someone who has passed out often leads people to question whether rubbing alcohol is an effective tool for restoring consciousness.
Clarifying the Common Misconception: Alcohol vs. Ammonia
The confusion stems from misidentifying the agent used to revive someone who has fainted. The correct substance is “smelling salts,” which are ammonia inhalants primarily composed of ammonium carbonate. This compound releases a pungent, irritating gas.
The potent ammonia gas stimulates the trigeminal nerve, the fifth cranial nerve responsible for transmitting sensation from the face and nasal cavity. The intense irritation triggers an involuntary, sudden inhalation reflex.
This abrupt shock causes a sympathetic nervous system response, countering the vagal response that leads to fainting. The intent is to rapidly increase heart rate and blood pressure, forcing the person to gasp and regain consciousness. Ammonia provides a physiological jolt, not a subtle aromatic stimulus.
Physiological Reasons Why Alcohol Does Not Help
Rubbing alcohol, typically isopropyl alcohol or diluted ethanol, is a fundamentally different chemical agent than ammonia in this context. While pure ethanol is technically listed as an irritant that can activate the trigeminal nerve, the mild vapor released by a typical rubbing alcohol swab is not potent enough to elicit the necessary physiological shock. Unlike the highly volatile and caustic ammonia gas, the vapor from rubbing alcohol does not possess the strong irritant properties required to forcefully stimulate the trigeminal nerve and trigger the sudden inhalation reflex.
Fainting is a circulatory event where the brain’s blood supply is temporarily insufficient. The mild, non-irritating scent of alcohol vapor does nothing to address this underlying issue of poor cerebral blood flow. It cannot provoke the rapid sympathetic nervous system activation needed to raise the heart rate and blood pressure. Relying on the vapor of rubbing alcohol as a revival method is ineffective because it lacks the chemical mechanism to counteract the temporary collapse of the circulatory system.
Appropriate Response and First Aid for Fainting
A person who has fainted will typically recover consciousness on their own within a minute or two once they are lying flat. Appropriate first aid focuses on restoring blood flow to the brain, not on olfactory stimulation. If someone faints, gently lay them flat on their back to prevent further injury from the fall.
The most beneficial action is to elevate their legs approximately 12 inches above the heart, using gravity to help return blood to the brain. Also, loosen any restrictive clothing, particularly around the neck and waist, to ensure clear airways and circulation. Check to ensure the person is breathing and has a pulse.
Medical attention is necessary if the person does not regain consciousness within two minutes, or if they sustained a head injury during the fall. Serious symptoms requiring an immediate call for emergency help include chest pain, confusion, or difficulty speaking after waking up. Once conscious, the person should remain lying down for several minutes before slowly attempting to sit up.