Always do a skin test prior to each application. Mix pea sized amounts of Herbatint™ color and Developer and apply to skin (behind ear or on forearm below elbow). Leave on skin for 48 hours taking care not to wash off during this time. If you experience any reaction during this time (itchiness, swelling, redness) do not use the product. The same test can be applied to Vegetal if you are in any doubt as to sensitivity to the product ingredients. Always do a strand test. It may be "Cinnamon Twist" on the box but it may become "Tropicana' on your tresses Herbatint can be safely applied to hair that has been colored with another product that is hydrogen peroxide based. On the first occasion however, the color might be slightly affected by the chemical pigments left by the previous product. Do not use Herbatint if you have colored your hair with a Henna based product and this Henna is still on your hair. Only color clean hair - product residue could interfere with developing color Choose a color two or three shades lighter than your natural tone. Rub Royal Cream around the hairline and wear rubber gloves to stop skin staining. For shades that are a big contrast to your natural hair color, consult Marie at 877-699-4400. If you have recently permed or straightened your hair, wait 2 weeks before using Herbatint. Don't use your best fluffy white towels, unless you fancy wearing this seasons tie-dyed look