Most liquid drain cleaners are heavier than water and will seek out the stoppage, even if the sink, tub or bowl is full of water.
Cleaners are typically a combination of potassium hydroxide, which turns grease to soft soap, and thioglycolic acid, that dissolves hair. Others may contain sodium hydroxide, sulfuric acid or lye.
Toxic liquids should carry warnings and must be used with caution.
DIY Frequently Asked Questions / Chemicals')">
Used to clear stopped-up drains by chemical action.