A cytotoxin is an agent that kills cells
Necrosis
The medical terminology combining form -cidal is an adjectival suffix meaning "killing." For instance, a fungicidal agent kills fungus, and a virucidal agent kills viruses.
Impetigo is a Latin word derived from impetus. Impet- (meaning 'attack') + -igo (suffix).
A pediculocide kills lice. It is a class of insecticides.
antibiotic
An antibacterial or a bacteriocidic substance kills bacteria.
Samarium doesn't kill cancer cells. A radioactive isotope of samarium (samarium-153) is used in a chemotherapy agent, but it's the radiation, not the samarium, that kills the cancer cells.
two
it kills bacteria in the colon
It's an old myth that alcohol kills brain cells.
A substance that kills cells is known as a toxin. There are toxins in the foods and beverages that are consumed everyday.
Neither, That alcohol (or drugs) kills brain cells is an urban myth.
Killer T Cells