An agent derived from acetohydroxamic acid with potential antineoplastic activity. Caracemide inhibits ribonuclease reductase, resulting in decreased DNA synthesis and tumor growth; it also inhibits acetylcholinesterase. In vivo, caracemide contributes to the formation of the neurotoxin methyl isocyanate; this effect, along with the agent's acetylcholinesterase activity, may be responsible for the severe central nervous system toxicity observed in clinical trials. (NCI04)