又搜了搜，人类用海娜粉来染色已经有5000年的历史，FDA允许用作染发剂，但不可以直接用在皮肤上

Regulation
The U.S. FDA has not approved henna for direct application to the skin. It is, however, grandfathered in as a hair dye and can only be imported for that purpose.[38][42] Henna imported into the U.S. that appears to be for use as body art is subject to seizure,[43] but prosecution is rare. Commercial henna products that are adulterated often claim to be 100% natural on product packaging in order to pass import regulations in other countries.


【 在 likebaby 的大作中提到: 】
: 纯天然的，一直掉色。我每次用白色毛巾擦头发会成黄色的，然后热水洗一下，不用洗衣服就又变白色了。头发的颜色过两个多月就淡了。
:
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FROM 173.38.117.*