Mammals are treated for infections or for conditions associated with pathologically
proliferating mammalian cell growth by administration of a manipulator of nitrosative
stress to selectively kill or reduce the growth of the microbes or helminths causing
the infection or of host cells infected with the microbes or of the pathologically
proliferating mammalian cells. Novel agents include -alkyl-S-alkyl-homocysteine
sulfoximines wherein the -alkyl contains 2 to 8 carbon atoms, and the S-alkyl
contains 1 to 10 carbon atoms. Mammals in need of increased nitrosative stress
defenses are treated, e.g., humans at risk for a stroke because of having had a
transient ischemic attack, are treated. Treatments to increase nitrosative stress
defenses include repeated administrations of low doses of manipullators of nitrosative
stress so that subject treated has increased tolerance to nitrosative stress. Mammals
are treated for protozoal infections by systemic administration of L-buthionine-S-sulfoximine
and agent that increases nirtrosative stress.