Caustic soda can work chemically, but it is too dangerous for the typical household toilet unblocking scenario. Avoid it.

| Method | Effectiveness | Safety | Notes | |--------|--------------|--------|-------| | | High for simple clogs | Very safe | First-line tool for toilets. | | Toilet auger / snake | Very high | Safe | Physically breaks or retrieves clogs. Inexpensive. | | Hot water + dish soap | Moderate | Safe | 1/4 cup dish soap + bucket of hot (not boiling) water; let sit 20 min. | | Baking soda + vinegar | Low (mild) | Safe | Fizzes but rarely clears major blockages. | | Enzymatic cleaner | Low-moderate | Safe | Takes hours but eco-friendly. Good for slow drains. | | Caustic soda | High | Dangerous | Only as last resort, with precautions. | 7. Conclusion & Recommendation Do not use caustic soda as a first or even second resort for a blocked toilet. The risk of cracking the porcelain, causing chemical burns, or damaging your plumbing outweighs the convenience. For 90% of toilet blockages, a flange plunger or toilet auger will solve the problem safely.

If the blockage persists after mechanical attempts, call a plumber. They can use professional-grade tools or safe chemical treatments without endangering you or your toilet.