Alcohol (Ethanol): general

Ethanol is the alcohol found in alcoholic drinks [1]. It's a clear, colourless liquid with a characteristic smell [2], and it's mildly toxic [1]. It occurs both naturally and as a manufactured chemical [2], and beyond drinking it turns up in solvents, perfumes, toiletries, disinfectants, preservatives, polishes, fuel additives, and drug manufacturing [2] — hand sanitiser gels can run up to 95% ethanol [3]. In drinks, it's produced by fermentation: yeast added to a sugar solution breaks carbohydrates down into ethanol and CO2 [4], the same process that occurs naturally wherever sugars ferment [5]. Humans have been drinking it for a very long time — at least 8000 years in the Middle East and possibly 9000 in China, where residue on Neolithic pottery points to early alcoholic beverages [4][1].

One thing that sets ethanol apart from other alcohols: people can drink it in a pure state without it being fatal on that basis alone, unlike methanol, butanol, or propanol [5]. That doesn't mean pure or high-strength ethanol is safe to drink casually — it's still the same mildly toxic, flammable compound used industrially [1][2].

As with depressants generally, this class of drugs slows central nervous system activity — lowering heart rate, breathing rate, and blood pressure, and producing drowsiness, confusion, and unconsciousness at high doses [6]. The signs of a depressant overdose are shallow or stopped breathing, blue lips or fingertips, unconsciousness, snoring or gurgling, and a weak or absent pulse [7]. If someone isn't breathing, start CPR and call 911 immediately [8]; naloxone will not reverse a depressant-only overdose [8].

Start low and go slow [9]. Don't use alone. As with depressants generally, avoid mixing with other depressants or opioids [9]. Have a plan for emergencies, including someone sober who can act if things go wrong [9].

References

1. Ethanol — ChemEurope
2. Ethanol: general information - GOV.UK — UK Health Security Agency (via GOV.UK)
3. Compendium of Chemical Hazards — Public Health England (via GOV.UK)
4. Ch. 17 Chemistry Matters—Ethanol: Chemical, Drug, and Poison - Organic Chemistry | OpenStax — OpenStax (Rice University)
5. Ethanol - StatPearls - NCBI Bookshelf — National Center for Biotechnology Information (NCBI)
6. Depressants — Australian Drug Foundation (ADF)
7. Depressant overdose signs - Rapid Action Drug Alerts and Response (RADAR) — Public Health Scotland
8. Depressants Overdose Response — Indiana Department of Health
9. Safer-use Strategies: Downers/Depressants — University of Washington HARRT Lab