Can I use this black dye on hair that has been recently bleached or permed, and what precautions should I take?

Yes, you can use this dye on previously bleached, highlighted, or permed hair, but it requires careful consideration. Chemical processes like bleaching and perming alter the hair's internal structure, making it more porous and fragile. This heightened porosity means the hair will absorb the permanent dye pigment very quickly and intensely, potentially resulting in an extremely dark, sometimes flat color that may be harder to lift later. More importantly, applying another chemical process to already compromised hair increases the risk of over-processing, which can manifest as extreme dryness, brittleness, and breakage. The product's own guidance advises being extra careful if your hair is very damaged or recently chemically treated. The essential precaution is to perform a strand test on a section of your hair that represents its current condition. This allows you to see the final color development and observe how your hair tolerates the product before committing to a full application. It is also sensible to ensure your hair is in the best possible condition beforehand with a course of deep conditioning treatments. If you have any doubts, or if your hair is severely damaged, consulting a hairdresser for professional assessment and application is the safest approach to avoid further harm.