Onion

What it does

Onion is a kitchen staple containing quercetin, sulfur compounds, and fermentable fibers. In natural-health teaching, including Barbara O'Neill's, it appears as a poultice for ears, chest, and skin, and as a juice for hair and general health. Supplements sell onion extracts and powders. This record grades the whole food and its traditional preparations.

What the research says

• Onion juice for patchy hair loss: one small, striking, unreplicated trial

  Evidence: emerging. Sharquie 2002 (Journal of Dermatology): 62 patients with alopecia areata applied crude onion juice or tap water twice daily; by eight weeks, regrowth appeared in 86.9 percent of the onion juice group versus 13 percent of controls. A real randomized result, and the only one of its kind: two decades on, no larger trial has confirmed or refuted it, and the smell alone limits adherence. This is the most interesting evidence in the onion file and it is one 62-person study.

• Onion poultices for earache, congestion, and 'drawing out' infection: traditional use, no trials

  Evidence: weak. The warm-onion poultice is a fixture of folk practice and of the natural-health teaching that brought this record into the queue. No clinical study tests it for any indication. Warmth itself soothes ear pain, which is likely the active ingredient in the tradition.

• Blood pressure and bone claims are extrapolations, not onion trials

  Evidence: weak. Onion is rich in quercetin, and quercetin-rich onion peel extracts have a small trial showing modest pressure reductions in hypertensive adults; that evidence belongs to concentrated extracts and to this library's quercetin record. Eating onions as part of a vegetable-rich diet carries the usual confounded cohort associations and no onion-specific outcome data.

Onion is a healthy food with a nearly empty clinical file: one small positive trial in a niche condition, one extract literature that belongs to another record, and a set of poultice traditions no researcher has ever tested. Nothing here is dangerous at food doses, and nothing here is established either. D+ is the grade for a benign food whose supplement-grade claims rest on a single 62-person study and folk practice.

Is it worth it?

Evidence (D+) sits far below the leaderboard floor, so the worth-it grade is capped at C+; the derived value lands at C- on food-level cheapness alone. About $4 a month at food amounts. Derived from the October 2026 worth-it model.