It is not harmful to wash your hair with soap locust and plant ash.

According to records, ancient people used plant ash to wash their hair, because plant ash contains a large amount of alkali, which can effectively remove oil from the hair. But it needs to be washed several times with clean water to clean it. Ancient people used saponin or polyporus to wash their hair. Polyporus is used by wealthy people. Some spices are added to Polyporus, which gives it a strong aroma. Ordinary people use soap locust to wash their hair.

Both soap locust and plant ash are natural and are not harmful to hair.