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Carbolic acid affects the human body in a variety of ways. It was originally an antimicrobial compound. In the mid-1800s, American surgeon Joseph Lister used carbolic acid to clean and dress wounds, reports MedicineNet.com. When administered in diluted strength, it is particularly useful as a topical anesthetic, and can relieve toothache pain. When applied in more concentrated formulations, however, carbolic acid can behave as a poison, in which case it targets the nervous system of the human body with dire effects.

Carbolic Acid Poisoning

The taking of full-strength carbolic acid orally causes acute gastroenteritis (inflammation of the stomach and intestines), which leads to vomiting, collapse and death. Upon ingestion of the acid, it energizes the vascular-motor and respiratory centers and paralysis quickly occurs thereafter. The heart slows to the point of paralysis as well. Respiration ceases after an increased breathing pattern. All reflexes essentially tamp down until the brain and spinal cord are utterly depressed and coma ensues.

Respiratory Paralysis

Carbolic acid affects respiration as it oxidizes in the body. The lungs partially expel the acid in the form of gas, and the kidneys expel it in the form of urine. Carbolic acid gives urine a smoky quality. A medium dose of the substance will tend to halt, or paralyze respiration, whereas a larger amount of the acid will stop the heart from beating. The telltale sign that a person died from carbolic acid poisoning is in the blood. Following death, the blood takes on an exceedingly dark color and will not coagulate, or clot.

Medicinal Effects

No longer used as an antiseptic because other more effective agents replaced it, carbolic acid has many other efficacious medicinal utilities today. As a 5 percent solution, it relieves skin itching, reports Henriette's Herbal Homepage. As a 1 percent solution, it works as a gargle. It's efficacious against the throat pain of tonsillitis. It's proven safe and effective against nausea and vomiting when taken as a one-quarter-grain dose. Also, in a very diluted solution of up to 5 percent, it serves as a spray for chronic lung infections. Other problems it targets include abscesses, endometritis, parasitic skin disease, synovitis and ulcers.