It is closely related to the natural alkaloid colchicine with the replacement of the acetyl group on the amino moiety with methyl, but it is less toxic.

It depolymerises microtubules and limits microtubule formation (inactivates spindle fibre formation), thus arresting cells in metaphase and allowing cell harvest and karyotyping to be performed.

Detached microtubules with unprotected minus end depolymerize with time.

Demecolcine inhibition of microtubules causes aneuploidy in mitotic cells where the microtubules fall apart or are suppressed before they can complete their function of pulling chromosomes into the daughter cell, also known as nondisjunction of chromosomes.

[5] Demecolcine, depending on dose, has also been found to cause DNA fragmentation of chromosomes in micronuclei when nondisjunction occurs.