Despite claims that GSE has antimicrobial effects,[11] there is no scientific evidence that GSE has such properties.[2][3] Some evidence indicates that the suspected antimicrobial activity of GSE was due to the contamination or adulteration of commercial GSE preparations with synthetic antimicrobials or preservatives.[1][2][12] These chemicals were not present in grapefruit seed extracts prepared in the laboratory, and GSE preparations without the contaminants were found to possess no detectable antimicrobial effect.[1] Although citrus seed extract is sold in health food markets,[12] there is no good evidence for any antimicrobial activity.[1]