Can I use this on hair that has been bleached, permed, or chemically coloured recently?

The source advises caution if your hair is heavily bleached or recently chemically coloured. Bleached hair is highly porous and can grab plant pigment unevenly, sometimes producing a darker, warmer, or even greenish cast on very light blonde bases. Recently permed or relaxed hair may be more fragile; the paste's drying time and the slight astringency of tannins can increase brittleness. If you have used oxidative dye within the last 4–6 weeks, residual chemicals can interact unpredictably with the botanical powders. Before full application, do a strand test on a hidden section: mix a small amount, apply, leave for the intended time, rinse, and wait 24–48 hours to see the true developed shade and check hair condition. If the strand test looks uneven or the hair feels overly dry, consider a deep conditioning treatment first or wait until the chemical history grows out.