Question: how much hydrogen peroxide should i put in my bath?
Answer: The usual recommendation is ½ to 1 cup of 35% hydrogen peroxide for a hydrogen peroxide bath. That's equal to 6 to 12 cups of 3% hydrogen peroxide. Usually a brown bottle from the drugstore is 2 cups worth, so that would be 3 to 6 bottles of 3% in a bathtub.