4-(Dimethylamino)-1-methylpyridinium is a monoquaternary pyridinium salt with anticholinesterase and antiproliferative activities. It inhibits cholinesterase activity in rat brain homogenates with a K value of 33 μM and yeast choline kinase (ChoK) with an IC value of 17 μM. 4-(Dimethylamino)-1-methylpyridinium also has antiproliferative activity against HT-29 colon cancer cells (IC = 2 μM).