Written by a parent, not a doctor. Nothing here is medical advice.

Childhood Cancer Lantern
Search Saved
Medicine

Vincristine

Updated September 2026.

Also known as: Oncovin

Stops cells from dividing by jamming the scaffolding they build to pull their chromosomes apart.

Vincristine is a chemotherapy drug given through the IV line or port. It comes from the Madagascar periwinkle plant and has been part of childhood leukemia treatment since the 1960s.

Inside a cell that is about to divide, vincristine sticks to tubulin, the protein the cell uses to build a temporary scaffold (the spindle) that pulls the two copies of its chromosomes apart. With the scaffold jammed, the cell gets stuck halfway through dividing and usually dies. Leukemia cells divide constantly, so they are hit hardest.

I made an everyday analogy and a more scientific visualization of vincristine.

Everyday analogy

Vincristine is like a jammed curtain track.

Vincristine is like a jammed curtain track. In a small theatre, a yellow-skinned stagehand pulls a continuous cord twice. Connected runners roll along the exposed track and the pleated curtains gather at the sides. The view slides to a fresh, closed-curtain comparison. A hand lowers a teal stop onto the track beside the leading runners, visibly opens its fingers, and withdraws. The stagehand makes two restrained attempts to pull the cord, but the leading runners stay fixed and the curtains remain closed. The stagehand releases the cord, reaches to the wall dimmer with the other hand, and lowers the slider. The stage lights fade while the intact curtains remain visible. The show cannot go on. The teal jam represents vincristine disrupting the tiny structures used for cell division. The curtains moving apart represent copied genetic instructions separating. The lights fading gently suggest a possible outcome: a cancer cell unable to divide can die. This is an analogy, not a literal picture of the medicine or of cell death. The final frame holds. UPDN LIGHTS The curtains open The track is jammed The show cannot go on

1 / 3 The curtains open

The curtains open

  • The teal jam represents vincristine disrupting the tiny structures a cell uses to divide.

  • The track and runners are like the machinery that separates copied genetic instructions. Opening the curtains represents those copies moving apart so the cell can divide.

  • When division stays blocked, a cancer cell can die. The stage lights fading suggest this possible outcome; the curtains themselves stay intact.

Press play below for a more accurate visualization.

Interactive visual

How vincristine jams the machinery a leukemia cell uses to divide

Poster for How vincristine jams the machinery a leukemia cell uses to divide
Read transcript

## 1. Arrival in bone marrow Vincristine is given into a vein. The blood carries it into the bone marrow, where leukemia cells crowd together and divide. This leukemia cell is about to divide. To split into two, it must first share out its chromosomes, one full set each. ## 2. Through the cell membrane Vincristine dissolves into the cell membrane, so it can pass into the cell without a door protein. ## 3. Sharing the chromosomes The cell has copied its chromosomes, the packages that hold its DNA. Each new cell must receive one complete set. So it builds a spindle: fibres from two poles that grow and shrink until every chromosome is caught and pulled into line. ## 4. A searching fibre tip Each fibre stacks tubulin bricks. Adding or shedding bricks makes its tip grow or shrink, so it can search for a chromosome. ## 5. Division stalls Vincristine binds tubulin at the fibre tip, suppressing growth and shortening, so the tip stops searching. Frozen fibres cannot catch or pull the chromosomes. Several stay loose, so the cell cannot finish dividing. ## 6. Self-destruct and cleanup The cell has a checkpoint that waits until every chromosome is caught. Stuck for hours, it switches on its self-destruct program. Its mitochondria leak a signal. Dormant enzymes called caspases wake up and take the cell apart from inside. The cell shrinks into many small sealed packets. The body's cleanup cells swallow them, and the leukemia cell is gone.

Side effects

The full list, kept up to date:

Where I read this