Monomethylhydrazine (mono·meth·yl·hy·dra·zine) (CH3NHNH2) is:

  • a rocket fuel used in bipropellant rocket engines.
  • a toxin found in many species of Gyromitra mushrooms (aka False Morels), acting as an antagonist to pyridoxine; six or more hours after ingestion, patients develop headache, dizziness, malaise, and vomiting, occasionally progressing to delirium, coma, and convulsions.