Dropping a dishwasher tablet into a toilet can be very reactive, and here’s what happens step by step:

What Happens Chemically

Effervescence: Most dishwasher tablets contain sodium carbonate, sodium percarbonate, and enzymes. When they contact water, especially warm water, they start fizzing and releasing oxygen, similar to a cleaning effervescent tablet.

Stain and Scale Removal: The oxidizing agents (like sodium percarbonate) can break down grime, urine stains, and limescale in the bowl. This is why some people use them as an emergency toilet cleaner.

Foaming: You may notice bubbling or foam, which helps lift deposits off surfaces.

Enzymatic Action: Enzymes in some tablets can help break down organic matter like leftover waste.

Safety Notes

Do not flush immediately if the tablet is still reacting vigorously; the foaming can splash.

Avoid mixing with other chemicals, especially bleach. Dishwasher tablets contain oxidizers, and mixing with bleach can create chlorine gas, which is dangerous.

This is okay as a short-term cleaning hack, but not a substitute for proper toilet cleaner.

Summary

Basically, it fizzes, bubbles, and helps break down stains, giving your toilet a quick scrub-like effect.