Although consumers’ need for a healthy and sustainable lifestyle drives natural cosmetics consumption, various claims of natural cosmetics make consumers confused and distrustful. This study aimed to explore factors that affect consumers' purchasing behavior of natural cosmetics under the theoretical framework of planned behavior (TPB). The study adopted the qualitative method of purposive sampling. Semi-structured interview technique and thematic analysis were used to collect and analyze data from 21 consumers of natural or traditional cosmetics living in Uppsala. The results showed: consumers had uncertain attitudes towards buying natural cosmetics, which had no obvious impact on the purchasing behavior; the perceived social pressures from family, relatives, groups, etc. had a clear positive impact on the purchasing behavior; online purchasing, recommendation from others, and sustainable lifestyle facilitated the purchasing behavior; high price, inconvenient purchasing location, lack of knowledge, non-harmonized certifications, etc. led to the inconsistency between consumers' purchasing intention and actual purchasing behavior. Product knowledge was explored as an important resource that consumers need. The above findings can be used to improve marketing strategies like harmonized certifications. This study also paves the way for future quantitative verification of these factors.