Bigen and henna are not the same.
Bigen has chemicals in it.
Ingredients: sodim perborate, cellulose gum,
P-Phenylenendiamine sulfate, m-aminophenol, sodium carbonate, disodium lauryl sulfosuccinate, magnesium stearate, fragrance, O-Aminophenol, P-Aminophenol.
P-Phenylenendiamine sulfate do NOT have a very good rep
http://en.wikipedia.org/wiki/P-Phenylenediamine
Henna, lawsonia inermis is a plant ground to powder to dye skin, hair, etc
http://en.wikipedia.org/wiki/Henna