Ammonium chloride?

Ammonium chloride is a white, crystalline salt with the formula NH4Cl. It’s made from ammonia (NH3) and hydrochloric acid (HCl).

Common uses
- Food additive: Used as an acidity regulator and yeast nutrient in some foods (often listed as E510). It’s also used in certain candies and pretzels in some countries.
- Medicine (historical/limited use): Historically used as an expectorant in cough syrups and as a urinary acidifier, but these uses are less common today and not for self-treatment.
- Laboratory and industry: A common lab reagent; used in buffers (e.g., ammonium chloride/ammonia buffers). Also used as a flux in soldering and in some metal finishing and textile processes.

Safety and handling
- Generally low hazard in small amounts, but concentrated solutions and dust can irritate skin, eyes, and the respiratory tract.
- Ingestion of large amounts can be harmful; inhalation of dust or mists should be avoided.
- Concentrated ammonium chloride is corrosive; keep away from skin/eyes and heat.
- People with kidney disease, acid-base disorders, or those taking certain medicines should use with caution and typically under medical advice.

If you have a specific angle in mind—e.g., how it’s used in a particular product, its safety in pregnancy, dosing for a medical use, or how it behaves in chemistry labs—tell me and I’ll tailor the info.