One ingredient that is ever-present in traditional Eastern Indian self-care is mustard oil. Mustard oil has been used extensively in household food and body-care practices in Assamese culture. It is also used in other elements of Assamese culture, like its ritual employment in an Assamese wedding ceremony through Tel Diya, where mustard oil is applied all over the bride. This custom of oiling is bigger than just a hair-care process, it is a physical ritual of the family performed by mothers, grandmothers, and others.
According to a study published in the National Library of Medicine, mustard oil has been used in hair care for many years in India, and studies have suggested that it may have some antimicrobial and antifungal effects.
https://pubmed.ncbi.nlm.nih.gov/11413497/
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