There are many colors out there, full of chemicals and toxins, cover ineffectively, and natural is better here. These items also make hair breakage, irritation, allergy and cancer even. No more dyes, we  as humans dyed hair in various ways in the past, naturally. Turmeric, henna, senna, indigo are the plants you need. This recipe makes the hair dark.

Source: Color The Hair Naturally And Be Amazed | Herbs Remedies