Symmetrical dimethylhydrazine (SDMH), or 1,2-dimethylhydrazine, is the organic compound with the formula (CH3NH)2.

Both isomers are colorless liquids at room temperature, with properties similar to those of methylamines.

Symmetrical dimethylhydrazine is a potent carcinogen that acts as a DNA methylating agent.

[5][6] The compound has no commercial value, in contrast to its isomer unsymmetrical dimethylhydrazine (1,1-dimethylhydrazine, UDMH), which is used as a rocket fuel.

[8] It is used to induce colon tumors in experimental animals—particularly mice and feline cell samples.